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  • Analytical Chemistry and Spectroscopy  (7,842)
  • ASTROPHYSICS  (5,054)
  • Animals  (4,806)
  • AERODYNAMICS  (3,067)
  • 1995-1999  (5,562)
  • 1985-1989  (15,206)
  • 1925-1929  (1)
Collection
Keywords
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Phylogenetic position of Dictyostelium inferred from multiple protein data sets (1995)
    Springer
    Journal of molecular evolution 41 (1995), S. 238-246 
    Details
    ISSN: 1432-1432
    Keywords: Cellular slime molds ; Animals ; Fungi ; Plantae ; Maximum-likelihood method ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phylogenetic position of Dictyostelium inferred from 18S rRNA data contradicts that from protein data. Protein trees always show the close affinity of Dictyostelium with animals, fungi, and plants, whereas in 18S rRNA trees the branching of Dictyostelium is placed at a position before the massive radiation of protist groups including the divergence of the three kingdoms. To settle this controversial issue and to determine the correct position of Dictyostelium, we inferred the phylogenetic relationship among Dictyostelium and the three kingdoms Animalia, Fungi, and Plantae by a maximum-likelihood method using 19 different protein data sets. It was shown at the significance level of 1 SE that the branching of Dictyostelium antedates the divergence of Animalia and Fungi, and Plantae is an outgroup of the Animalia-Fungi-Dictyostelium clade.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00170678
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  • 2
    Electronic Resource
    Electronic Resource
    Evolutionary relationships of eukaryotic kingdoms (1996)
    Springer
    Journal of molecular evolution 42 (1996), S. 183-193 
    Details
    ISSN: 1432-1432
    Keywords: Small-subunit ribosomal RNA ; Phylogeny ; Animals ; Fungi ; Plants ; Alveolates ; Heterokonts ; Stramenopiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary relationships of four eukaryotic kingdoms—Animalia, Plantae, Fungi, and Protista—remain unclear. In particular, statistical support for the closeness of animals to fungi rather than to plants is lacking, and a preferred branching order of these and other eukaryotic lineages is still controversial even though molecular sequences from diverse eukaryotic taxa have been analyzed. We report a statistical analysis of 214 sequences of nuclear small-subunit ribosomal RNA (srRNA) gene undertaken to clarify these evolutionary relationships. We have considered the variability of substitution rates and the nonindependence of nucleotide substitution across sites in the srRNA gene in testing alternative hypotheses regarding the branching patterns of eukaryote phylogeny. We find that the rates of evolution among sites in the srRNA sequences vary substantially and are approximately gamma distributed with size and shape parameter equal to 0.76. Our results suggest that (1) the animals and true fungi are indeed closer to each other than to any other “crown” group in the eukaryote tree, (2) red algae are the closest relatives of animals, true fungi, and green plants, and (3) the heterokonts and alveolates probably evolved prior to the divergence of red algae and animal-fungus-green-plant lineages. Furthermore, our analyses indicate that the branching order of the eukaryotic lineages that diverged prior to the evolution of alveolates may be generally difficult to resolve with the srRNA sequence data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02198844
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  • 3
    Electronic Resource
    Electronic Resource
    Segmentation and tracking of piglets in images (1995)
    Springer
    Machine vision and applications 8 (1995), S. 187-193 
    Details
    ISSN: 1432-1769
    Keywords: Tracking ; Segmentation ; Pigs ; Animals ; Computer vision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An algorithm was developed for the segmentation and tracking of piglets and tested on a 200-image sequence of 10 piglets moving on a straw background. The image-capture rate was 1 image/140 ms. The segmentation method was a combination of image differencing with respect to a median background and a Laplacian operator. The features tracked were blob edges in the segmented image. During tracking, the piglets were modelled as ellipses initialised on the blobs. Each piglet was tracked by searching for blob edges in an elliptical window about the piglet's position, which was predicted from its previous two positions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01215814
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  • 4
    Electronic Resource
    Electronic Resource
    Animal Consciousness and Ethics in Asia and the Pacific (1997)
    Springer
    Journal of agricultural and environmental ethics 10 (1997), S. 249-267 
    Details
    ISSN: 1573-322X
    Keywords: Animals ; Asia ; consciousness ; Australia ; Hong Kong ; India ; Israel ; Japan ; New Zealand ; The Philippines ; Russia ; Singapore ; Thailand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007774409131
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  • 5
    Electronic Resource
    Electronic Resource
    Multicomponent determinations by a membrane-discriminated gas phase analyzer and successive regression in the fiduciary region (1989)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 3 (1989), S. 601-608 
    Details
    ISSN: 0886-9383
    Keywords: Gas phase flow injection analysis ; Membrane-differentiated analysis ; Multicomponent determinations ; Successive linear regression ; Successive regression in fiduciary region ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A membrane-discriminated gas phase analyzer is proposed for multicomponent determinations. Nitrogen gas flows countercurrent through outer and inner channels in a tube-in-tube arrangement. The only communication between the two channels occurs through a 500 μm aperture covered by a porous PTFE membrane. A mixture of organic compounds (up to four components) is injected into the inner channel by a heated backflushed injector and the sample components diffusing into the outer channel are monitored by a flame ionization detector (FID). A calibration set, consisting of pure components, binary, ternary and quaternary mixtures (a total of 64 samples), provides the known data base: temporal profiles of the FID output as a function of sample composition. Although the overall response behavior is not a linearly additive function of individual analyte concentrations, the use of successive inverse multiple linear regression (while continually altering the choice of the calibration samples considered for the forward regression, on the basis of the most recent values of the predicted unknown sample composition) is shown to yield analytical results for unknown samples that are in good agreement with their true values.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180030408
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  • 6
    Electronic Resource
    Electronic Resource
    Product news (1989)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 3 (1989), S. 609-609 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180030409
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  • 7
    Electronic Resource
    Electronic Resource
    Editorial (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 1-2 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090102
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  • 8
    Electronic Resource
    Electronic Resource
    Deconvolution algorithms for instrumental applications: A comparative study (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 3-20 
    Details
    ISSN: 0886-9383
    Keywords: Deconvolution algorithms ; Instrumental analysis ; Spectrometry ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deconvolution algorithms for measurand reconstruction are considered. Their metrological and numerical properties are briefly characterized. Six algorithms most frequently used for instrumental applications are selected for closer analysis. Their comparative study is based on the use of spectrometric-type synthetic data, calorimetric-type synthetic data and spectrometric real-world data. Conclusions concerning computational complexity and accuracy of the compared algorithms as well as their metrological applicability are drawn.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090103
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  • 9
    Electronic Resource
    Electronic Resource
    FT-NIR Atlas, Michael Buback and Hans Peter Vogele, VCH, Weinheim, 1993, ISBN 3-527-28567-9, iv + 1067 pp., hardcover DM 880 (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 67-68 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090107
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  • 10
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090201
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  • 11
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090301
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  • 12
    Electronic Resource
    Electronic Resource
    Application of procrustean methods to mid-and near-infrared spectral data (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 125-135 
    Details
    ISSN: 0886-9383
    Keywords: Procrustean analysis ; FT-IR spectroscopy ; NIR spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Procrustean methods allow the fitting of a given matrix to another given matrix observed on the same objects. In the traditional approach orthogonal constraints are imposed upon the transformation matrix, whereas in the alternative approach Procrustean analysis may be performed without such constraints. The two methods (with and without constraints) were compared on data dealing with mid- and near-infrared spectra of oil. The aim was to reconstruct the mid-infrared spectral information using data from the near-infrared spectra. Unconstrained Procrustean analysis proved to be the more efficient for both the calibration and verification sets. Furthermore, the analysis of the transformation matrix between the two infrared ranges made it possible to indicate wavelengths and wave numbers corresponding to the same chemical groups.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090204
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  • 13
    Electronic Resource
    Electronic Resource
    A combined theory for PCA and PLS (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 91-123 
    Details
    ISSN: 0886-9383
    Keywords: H-principle ; PCA ; PLS regression ; latent variable models ; quadratic models ; sensitivity analysis ; outlier tests ; prediction variances ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We present here an algorithmic approach to modelling data that includes principal component analysis (PCA) and partial least squares (PLS). In fact, the numerical algorithm presented can carry out PCA or PLS. The algorithm for linear analysis and extensions to non-linear analysis applies to both PCA and PLS. The algorithm allows for combination of PCA and PLS types of models and therefore extends modelling to new types of models that involve combination of regression models and ‘selection of variation’ models, which is the idea of PCA-type models. The fact that the algorithm carries out both PCA and PLS shows that PCA and PLS are based on the same theory. This theory is based on the H-principle of mathematical modelling. The algorithm allows tests for outliers, sensitivity analysis and tests of submodels. These aspects of the algorithm are treated in detail. We compute various measures of sizes, e.g. of components, of the covariance matrix, of its inverse, etc. that show how much the algorithm has selected at each step. The analysis is illustrated by data from practice.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090203
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  • 14
    Electronic Resource
    Electronic Resource
    Pattern recognition analysis of near-infrared spectra by robust distance method (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 169-178 
    Details
    ISSN: 0886-9383
    Keywords: minimum volume ellipsoid (MVE) estimators ; robust distance method ; pattern recognition ; Hotelling's T2 statistics ; near-infrared spectra ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for pattern recognition analysis of near-infrared spectra has been developed using robust distances determined by minimum volume ellipsoid (MVE) estimators of multivariate location and scatter. Classical methods such as the Mahalanobis distance method often fail in the presence of a moderate number of outliers in a training data set, while robust distance methods can tolerate a considerably larger proportion of outliers in a training data set Outliers can be detected by their relatively large robust distances and can be excluded from a training set without a priori knowledge of the nature of the data set. In this paper the properties of a robust distance method are examined using near-infrared spectra of sulfamethoxazole and mixtures with its major degradation products, sulfanilic acid and sulfanilamide. The robust distance method successfully detected unacceptable samples (71.4%-89.3% (α = 0.05) or 78.6%-92.9% (α = 0.10)) even when they were inadvertently included in the training data set.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090304
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  • 15
    Electronic Resource
    Electronic Resource
    Data analyses or problem formulations? (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 226-228 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090309
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  • 16
    Electronic Resource
    Electronic Resource
    Expression of the reference value for proficiency tests (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 197-209 
    Details
    ISSN: 0886-9383
    Keywords: proficiency test ; true value ; homogeneity robust statistic ; standard ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Profficiency tests raise two types of problems: (i) the homogeneity of a sample must be carefully checked before using it as a reference material; (ii) it is necessary to define a conventional reference value (RV) in order to rank participants. Since these topics are poorly addressed in the literature, a reference material was specially prepared in order to propose a procedure for verifying homogeneity and to establish whether the algorithms classically used to compute the conventional true value have an influence on the conclusion of the test.The homogeneity of the sample was not perfect and univariate and multivariate techniques were used to demonstrate some analytes can be suspected as heterogeneous. However, this was considered adequate for introducing the sample in a large proficiency test organized between four laboratory associations which regularly perform such tests. Altogether more than 3000 measurements were collected and eight algorithms were applied to compute the RV on 14 analytes. Thus is was possible to demonstrate that some of these algorithms are better adapted than others. It is also obvious that some analytes are better suited to proficiency testing.It can be concluded from this work that some effort towards standardization would be profitable to check homogeneity or to compute the RV, especially since the economic weight of proficiency testing is becoming even more important with the development of certification accreditation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090306
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  • 17
    Electronic Resource
    Electronic Resource
    Interactive variable selection (IVS) for PLS. Part II: Chemical applications (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 331-342 
    Details
    ISSN: 0886-9383
    Keywords: partial least squares (PLS) ; variable selection ; IVS-PLS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: With the aim of developing PLS models with improved predictive properties, an interactive variable selection (IVS) approach for PLS regression was introduced in Part I of this series. IVS-PLS is based on a dimension-wise selective removal of single elements in the PLS weight vector w. IVS uses cross-validation (CV) as a guiding tool. The present paper illustrates the use of IVS-PLS on both simulated data and real examples from chemistry. In the first example, spectrophotometric data were simulated according to an experimental design. The objective was to see how IVS-PLS was influenced by different levels of noise in X and Y and by the number of predictor variables (K). The results of the modelling are shown as response surfaces. In addition, four real examples were modelled by the IVS-PLS technique. The real data sets were chosen to reflect different types of data from chemistry. For each example a comparison of ‘prediction error sum of squares’ (PRESS) between IVS-PLS and classical PLS is madeFor most of the examples containing many predictor variables IVS-PLS shows an improvement in predictive properties over classical PLS. Also, improvements for IVS-PLS2 (modelling of more than one y-variable) models were found. For data sets with a moderate number of variables the influence of the IVS method becomes less pronounced.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090502
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  • 18
    Electronic Resource
    Electronic Resource
    An extended strategy for exploratory multivariate image analysis including noise considerations (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 389-409 
    Details
    ISSN: 0886-9383
    Keywords: multivariate image analysis ; principal component analysis ; exploratory data analysis ; projection in multivariate space ; graphical visualization ; noise ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multivariate image analysis (MIA) is a powerful tool for many image segmentation and classification problems, but the interpretation and understanding of the original and resulting multidimensional (multivariate) data are not always easy. A strategy for MIA has been proposed which describes its usage on multivariate images for segmentation tasks. MIA starts with principal component analysis (PCA) and then continues with interactive analysis of the output from PCA. In this paper a number of extensions to MIA are proposed. The extensions are the suggestion to incorporate preprocessing of the multivariate image in MIA, the suggestion to use synthetic multivariate image models which create a clear-cut situation, and new visualization tools which improve the interactivity and understanding of the results. Extended MIA is applied on synthetic multivariate image data simulating a possible application with large noise, positron emission tomography (PET). As a result of the interactive analysis, suggestions for preprocessing emerge. The developed methodology for handling the noise is then applied on real PET image data with good results.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090506
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  • 19
    Electronic Resource
    Electronic Resource
    A correlation principal component regression analysis of NIR data (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 21-29 
    Details
    ISSN: 0886-9383
    Keywords: Near-infrared absorbance ; Partial least squares ; Principal component regression ; Root-mean-square error of prediction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of principal component regression (PCR) as a multivariate calibration method has been discussed by a number of authors. In most situations principal components are included in the regression model in sequence based on the variances of the components, and the principal components with small variances are rarely used in regression. As pointed out by some authors, a low variance for a component does not necessarily imply that the corresponding component is unimportant, especially when prediction is of primary interest. In this paper we investigate a different version of PCR, correlation principal component regression (CPCR). In CPCR the importance of principal components in terms of predicting the response variable is used as a basis for the inclusion of principal components in the regression model. Two typical examples arising from calibrating near-infrared (NIR) instruments are discussed for the comparison of the two different versions of PCR along with partial least squares (PLS), a commonly used regression approach in NIR analysis. In both examples the three methods show similar optimal prediction ability, but CPCR performs better than standard PCR and PLS in terms of the number of components needed to achieve the optimal prediction ability. Similar results are also seen in other NIR examples.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cem.1180090104
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  • 20
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    Electronic Resource
    Announcement (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. i 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090108
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  • 21
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    International chemometrics research meeting (ICRM) (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 137-138 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090205
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  • 22
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    Electronic Resource
    Simple encoding of infrared spectra for pattern recognition. 1: Statistical examination of the effectiveness and information content by factor analysis (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 143-168 
    Details
    ISSN: 0886-9383
    Keywords: pattern recognition ; infrared spectra ; factor analysis ; maximum likelihood method ; entropy of information ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spectral region from 700 to 3600 cm-1 is subdivided into several wave number intervals. The peaks in each interval are summarized by means of three encoding algorithms. Using a factor model of kcommon factors, the total extractable variacnce (com) of a given set of intervals is calculated and correlated with the redundancy of information in all these intervals. The value of com is verified by analysis of the factor loadings aik (factor pattern). Finally, the information content of some chosen sets of intervals coded by the three selected feature algorithms will be correlated to the probability of information flow through a serial-parallel network. The encoding using only wave numbers was found to be the most effective.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090303
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  • 23
    Electronic Resource
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    Diagnostics statistics in QSAR (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 211-221 
    Details
    ISSN: 0886-9383
    Keywords: diagnostics statistics ; QSAR ; MASCA ; principal component regression ; non-least squares regression ; types of multicollincarity ; flagged observations ; influential points ; high-leverage points ; outliers ; extra-carrier points ; random perturbation ; cluster correalation ; resampling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formal application of a Hansch analysis to a series of 3-quinuclidinyl benzylates (QNBs) led to a ‘statistically significant’ QSAR equation. In contrast, the application of the MASCA model has shown that the design matrix is unsuitable for each QSAR analysis: one sample member is an outlier but not a high-leverage or influential point; another one is an influential point, a high-leverage point and an extra-carrier point. The regressors of the design matrix are multicollinear without predictive model power. The result of such flagged observation and this type of multicollinearity is a multiple cluster correlation. The QNB series is a good example for ‘sampling artifacts’ where no practically important but artificial QSARs can be found.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cem.1180090307
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  • 24
    Electronic Resource
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    Stone and jonathan versus mager debate (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 230-231 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090311
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  • 25
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    A review of robust process design approaches (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 239-262 
    Details
    ISSN: 0886-9383
    Keywords: industrial experimentation ; parameter design ; quality by design ; robust design ; Taguchi method ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aim of this paper is to present a simple structured review of the different approaches to robust process design to clarify their similarities and dissimilarities. It is primarily written for practitioners who wish to understand and compare the main ideas of each approach and to apply them to their work. Two examples are used to illustrate the different approaches and their corresponding data analysis strategies: the first one is a constructed example on a pigment kneading process and the second one is real example dealing with the validation of an HPLC method. A comparison of the different approaches is provided and some practical recommendations are formulated.
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    URL: http://dx.doi.org/10.1002/cem.1180090402
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    PLS shrinks (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 323-326 
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    ISSN: 0886-9383
    Keywords: partial least squares ; biased regression ; ordinary least squares ; minimum length least squares ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An algebraic proof is given that in partial least squares (PLS) regression the Euclidean length of the estimator is shrunk in comparison with the ordinary least squares estimator or with PLS estimators based on a larger number of dimensions.
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    URL: http://dx.doi.org/10.1002/cem.1180090406
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    Masthead (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995) 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090501
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    A simple iteration algorithm for PLS regression (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 363-372 
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    ISSN: 0886-9383
    Keywords: PLS regression ; orthogonal expansion ; optimization ; Lagrange multipliers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple iteration algorithm that is faster and less memory-intensive than the NIPALS iteration algorithm for PLS regression is presented. The iteration algorithm is obtained by treating the orthogonal expansion or decomposition of a matrix X as an extremum problem subject to normalization and orthogonality constraint conditions and then solving the problem by use of the method of Lagrange multipliers. The main idea in this method is to find the transformation vector r. The latent variable t is expressed exactly as the linear combination of X-variables with the vector r so that the final regression coefficients can be conveniently provided. In the algorithm the recursion of the orthogonal projection is needed, which is derived by use of a matrix inverse formula. Algorithms are established from the equation for calculating the vector r that are suitable for dealing with three cases of large data sets. The first case is when the number of objects is very large, the number of variables is relatively small and the number of Y-variables is equal to or greater than the number of X-variables. The second case is when the number of objects is very large, the number of variables is relatively small and the number of X-variables is greater than the number of Y-variables. The last case is when the number of variables, either X- or Y-variables, or both, is very large and the number of objects is small.
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    Algorithm for finding an interpretable simple neural network solution using PLS (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 423-430 
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    ISSN: 0886-9383
    Keywords: PLS ; neural network ; training ; interpretable ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This communication describes the combination of a feedforward neural network (NN) with one hidden neuron and partial least squares (PLS) regression. Through training of the neural network with an algorithm that is a combination of a modified simplex, PLS and certain numerical restrictions, one gains an NN solution that has several feasible properties: (i) as in PLS the solution is qualitatively interpretable; (ii) it works faster than or comparably with ordinary training algorithms for neural networks; (iii) it contains the linear solution as a limiting case. Another very important aspect of this training algorithm is the fact that outlier detection as in ordinary PLS is possible through loadings, scores and residuals. The algorithm is used on a simple non-linear problem concerning fluorescence spectra of white sugar solutions.
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    URL: http://dx.doi.org/10.1002/cem.1180090508
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    Conference announcement (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 439-439 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090512
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    A PLS kernel algorithm for data sets with many variables and few objects. Part II: Cross-validation, missing data and examples (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 459-470 
    Details
    ISSN: 0886-9383
    Keywords: PLS ; kernel algorithm ; multivariate calibration ; EM algorithm ; cross-validation ; missing data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This is Part II of a series concerning the PLS kernel algorithm for data sets with many variables and few objects. Here the issues of cross-validation and missing data are investigated. Both partial and full crossvalidation are evaluated in terms of predictive residuals and speed and are illustrated on real examples. Two related approaches to the solution of the missing data problem are presented. One is a full EM algorithm and the second a reduced EM algorithm which applies when the number of missing values is small. The two examples are multivariate calibration data sets. The first set consists of UV-visible data measured on mixtures of four metal ions. The second example consists of FT-IR measurements on mixtures consisting of four different organic substances.
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    URL: http://dx.doi.org/10.1002/cem.1180090604
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    Orthogonal canonical variates for discrimination and classification (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 509-520 
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    ISSN: 0886-9383
    Keywords: canonical variates ; discriminant analysis ; partial least squares ; principal components ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new set of derived variables is proposed for exhibiting group separation in multivariate data on for preprocessing such data prior to discriminant analysis. The technique combines optimal features of canonical variate analysis and principal component analysis: the derived variables are linear combinations of the original variables that optimize the canonical variate criterion (ratio of between-group to within-group variance) but subject to the orthogonality constraints of principal components. In this formulation the canonical variates can be derived even when the within-group matrix is singular (i.e. when there are more variables than objects in the data matrix). A simple computational algorithm for extraction of these variables is proposed. The methods are illustrated on several data sets and compared with alternative techniques such as principal component analysis and partial least squares.
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    The Unscrambler®, Version 5.5. Multivariate analysis software for MS-DOS. Available from CAMO A/S, Olav Tryggvasons Gate 24, N-7011 Trondheim, Norway (Telephone: (+47) 7351 4966, Fax: (+47) 7351 4257) or from CAMO USA, 435 Blake Street, Menlo Park, CA 94025, U.S.A. (Telephone/Fax: (+1 415) 324-4286, Internet: teledyn@netcom.com). Single-copy price NOK 26 900 commercial, NOK 18 800 non-commercial, NOK 11 900 academic (1995)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 9 (1995), S. 527-529 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180090612
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    Gas chromatography mass spectrometry of some thermally labile urea pesticides (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 39-42 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of gas chromatography/mass spectrometry to three thermally labile phenylurea pesticides is reported. Using alcohols as solvents the decomposition of the pesticides is followed by a reaction in which esters of N-(3,4-dichlorophenyl)carbamic acid are formed. As these reactions occur during the gas chromatographic analysis, it is the esters which are identified in the mass spectrometer. The methyl ester is itself a pesticide so an erroneous conclusion about the original pesticide could be reached when methanol is the solvent.
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    252Cf plasma desorption fourier transform ion cyclotron resonance mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 43-45 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ions produced by 252Cf plasma desorption are detected by Fourier transform ion cyclotron resonance techniques. Results for CsI and N,N,N-trimethyl-p-aminophenolate iodide show the feasibility of the technique with high resolution (up to 11 000 at m/z 23) and good signal-to-noise ratio (up to 726).
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    Camera-ready BEMS short communications - guidelines for authors (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 47-48 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/bms.1200140111
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    BEMS short communication (camera-ready example) (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 49-50 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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    Forthcoming events (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 51-51 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/bms.1200140113
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    Fast atom bombardment mass spectrometry of butyloxycarbonyl protected (BOC) peptides (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 53-61 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fast atom bombardment positive ion mass spectra and the [M + H]+ collisional activation spectra of t-butyloxycarbonyl protected peptides and the unprotected analogues have been compared. It is concluded that sequence information, especially from the collisional activation spectra, can better be derived from the underivatized peptides than from the BOC-peptides.
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    Profiling and quantification of biogenic amines in wine by constant B2E linked scan mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 229-233 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The constant B2E linked scan is shown to be an excellent tool for the profiling of biogenic amines in wine samples. The fragment ion at m/z 169 of the dansylated amines is used for the precursor ion search in combination with direct sample evaporation. Besides the profile a semi-quantification may be achieved when using suitable amines as internal standards with standard deviations of 12-17%. More accurate results with standard deviations of 3-5% are obtained when using deuterated analogues as internal standards. Both methods are applied to the analysis of biogenic amines in synthetic mixtures and actual wine samples.
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    URL: http://dx.doi.org/10.1002/bms.1200140506
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    252-Californium plasma desorption mass spectrometry of glycerophospholipids (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 241-246 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 252-Californium plasma desorption mass spectrometry was applied to the study of five different classes of phospholipids namely phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine and phosphatidylinositol. Positive and negative ion spectra were compared to spectra obtained using other ionization techniques. Plasma desorption mass spectra provide useful information on the molecular weight of compounds from all classes, particularly in the case of phosphatidylserine - a class that has failed to show satisfactory quasimolecular ions with either Fast atom bombardment, FAB or Field desorption, FD. The observed fragmentation is also indicative of the structure of the studied compounds.
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    Quantitative analysis of S3341 in human plasma and urine by combined gas chromatography - negative ion chemical ionization mass spectrometry: 15 month inter-day precision and accuracy validation (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 289-293 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new quantitative assay for the determination of S3341, an alpha-2 agonist antihypertensive drug, has been developed using combined gas chromatography-negative ion chemical ionization mass spectrometry. The [M]-. ions from TFA derivatives of S3341 (m/z 276) and the internal standard (2H4)S3341 (m/z 280) are monitored simultaneously by selected ion monitoring. For S3341 concentrations ranging from the limit of detection (0.2 ng ml-1 using 1 ml of plasma) to 5 ng ml-1, the average assay precision (CV) is approximately 7% while the average assay accuracy (percentage of error) is 4%. Validation of the day-to-day precision and accuracy was realized after analysing control plasma samples (n = 295) concurrently with the biological samples collected during the pharmacokinetic studies conducted over 15 months. The average day-to-day precision (CV) and accuracy (percentage of error) are 10% and 6% respectively, thus indicating that this assay procedure routinely provides reliable analytical data.
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    Improvement in sensitivity of fast atom bombardment mass spectrometry of amino acids by di-isopropylphosphorylation (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 331-333 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive ion fast atom bombardment mass spectrometric sensitivities of seven amino acids and the corresponding di-isopropylphosphorylated derivatives were carefully compared. Results showed that an improvement in sensitivity by factors of 4-29, mostly above 10, were achieved after the derivatization. The chemical noise derived from glycerol matrix was also greatly reduced by this derivatization.
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    Analysis of cholesterol, cholesterol-5,6-epoxides and cholestane-3β,5α,6β-triol in nipple aspirates of human breast fluid by gas chromatography/mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 335-338 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for the quantitative determination of cholesterol and three of its major oxidative metabolites (the 5α,6α-epoxide, the 3β,5α,6β-triol, and the 5β,6β-epoxide) in a single sample of human breast fluid (2-50 μl), using gas chromatography/mass spectrometry with selected ion monitoring. High specificity and reliable quantification is achieved by the use of the inverse stable isotope dilution method, employing deuterium-labeled variants of the compounds as internal standards.
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    Simultaneous determination of pool sizes and fractional turnover rates, of deoxycholic acid, cholic acid and chenodeoxycholic acid in man by isotope dilution with 2H and 13C labels and serum sampling (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 609-611 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes a method for simultaneous determination of the kinetics of the three major bile acids in man using (2,2,4,4-2H4) deoxycholic acid, (24-13C) cholic acid and (24-13C) chenodeoxycholic acid. The gas chromatographic/mass spectrometric-selected ion monitoring technique used provided complete separation of deoxycholic acid, cholic acid and chenodeoxycholic acid, which permitted simultaneous measurement of isotope ratios for all three bile acids. Since measurement of all three pool sizes and fractional turnover rates in a single experiment requires different isotopic labels for deoxycholic acid and cholic acid, we investigated the in vivo stability and applicability of (2,2,4,4-2H4) deoxycholic acid as a stable isotope marker for isotope dilution studies in man. No consistent differences were observed between deoxycholic acid pool sizes and fractional turnover rates determined in serum samples after administration of (2,2,4,4-2H4) deoxycholic acid and (24-13C) deoxycholic acid. Simultaneous administration of (2,2,4,4-2H4) deoxycholic acid (24-13C) cholic acid and (24-13C) chenodeoxycholic acid and isotope ratio measurements in serum permitted determination of pool sizes and fractional turnover rates of the three major bile acid and the 7α-dehydroxylation fraction. Pool sizes, fractional turnover rates and synthesis rates (input rates) agreed well with data obtained previously with (24-13C) labels in independent studies.
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    Identification of new steroids in patients with 17α-hydroxylase deficiency by capillary gas chromatography/mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 633-637 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Urines of two children with 17α-hydroxylase deficiency contained a number of 5-pregnane- and pregnenediols, -triols and -tetrols with a hydroxy or oxo group in position 11 of the steroid ring. They are formed mainly from progesterone via 11-hydroxyprogesterone, pregnanolone and corticosterone, respectively, or from pregnenolone. Three metabolites not previously described, 16-hydroxypregnenolone, 6,21-dihydroxypregnanediol and 6-hydroxytetrahydrocorticosterone, were identified.
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    Gas chromatographic/mass spectrometric studies of the urinary metabolites of male rats given indan (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 649-651 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identified urinary metabolites of male rats exposed to indan are: 1- and 2-indanone; 1-, 2- and 5-indanol; 2-and 3-hydroxyl-1-indanone; and cis- and trans-indan-1,2-diol. Indan causes kidney damage in male rats in a manner similar to the cyclic hydrocarbons cis- and trans-decalin and JP-10. Lesions produced by indan occur only in male rats and not in female or control rats.
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    Routine gas chromatographic/mass spectrometric analysis of urinary organic acids. Results over a three-year period (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 663-668 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic acidaemias are an important part of inborn errors of metabolism. The biochemical diagnosis is based on gas chromatographic/mass spectrometric identification of urinary organic acids. Since 1973 we have used gas chromatographic analysis of the methyl esters of urinary organic acids. Mass spectral identification was performed only when an abnormal gas chromatographic profile was suspected. In 1983 we introduced routine gas chromatographic/mass spectrometric analysis organic acids. More than 1500 urine samples from 1000 children have been analysed and we encountered more than 40 abnormal profiles: 18 classical organic acidaemias (propionic, methyl-malonic, isovaleric, glutaric type I and 3-hydroxy-3-methyl glutaric acidaemias); 6 aminoacidopathies with excretion of branched chain keto acids (leucinosis) or succinylacetone (tyrosinosis type I); 14 massive dicarboxylic acidurias with excretion of suberyl and hexanoyl glycine and deficiency of the medium chain acyl CoA dehydrogenase in four patients. The use of gas chromatography/mass spectrometry routinely allows the identification of abnormal metabolites excreted in small amounts: β-methyl-crotonyl glycine indicative of biotin deficiency: γ-hydroxybutyric acid; and 3-methyl-glutaconic + 3-methy-glutaric acid is in a 3-methyl-glutaconic aciduria type II. Abnormal profiles due to metabolites of drugs as valproate, salicylate and barbiturate can be recognized immediately. This simple gas chromatographic/mass spectrometric system can lead to diagnosis, in one day, of rare but severe diseases needing a specific and early treatment.
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    Determination of serum cortisol by thermospray liquid chromatography/mass spectrometry: Comparison with gas chromatography/mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 717-722 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The determination of serum cortisol by thermospray liquid chromatography/mass spectrometry (LC/MS) has been assessed. The method incorporates stable isotope dilution and innumoadsorption extraction. [M + H]+ ions are monitored during LC/MS. The within-assay reproducibility is satisfactory (coefficient of variation 7% at a concentration of 190 ng ml-1), though inferior to that achieved with the (more lengthy) procedure of gas chromatography/mass spectrometry (GC/MS). Satisfactory agreement between LC/MS (y) and GC/MS (x) data was observed (y = 0.934x + 12.4 ng ml-1; r = 0.968; n = 14). It is concluded that the generation of precise reference data for the assessment of routine cortisol assays is at present better achieved by GC/MS. LC/MS, however, provides satisfactory quantitative data via a more simple and rapid method.
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    The alkylthio-isoindole derivatives of biogenic amines: A mass spectrometric study (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 737-738 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/bms.1200141208
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    Rapid quantification of 11 prostanoids by combined capillary column gas chromatography and negative ion chemical ionization mass spectrometry: Application to prostanoids released from normal human embryonic lung fibroblasts WI38 in a culture medium (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 25-32 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rapid and simultaneous quantification of 11 prostanoids has been carried out with a short-capillary gas chromatograph and negative ion chemical ionization (ammonia) mass spectrometer.The methoxime-trimethylsilyl ether-pentafluorobenzyl esters (MO-TMS-PFB) of nine prostanoids, PGA1, PGA2, PGB1, PGB2, PGD2, PGE1, PGE2, 6-oxo-PGF1α and TXB2 and the TMS-PFB of two prostanoids, PGF1α and PGF2α, were separated in less than 5.5 min on a bonded OV-1 capillary column 0.25 mm i.d. × 6 m (0.15 μm thickness) using hydrogen as a carrier gas. PGD2, PGE2, PGF2α, 6-oxo-PGF1α and TXB2 were quantified up to 2.5 fmol injected (0.1 pmol derivatized) and both PGA2 and PGB2 up to 25 fmol injected (1 pmol derivatized).In order to maintain the stability of the prostanoids containing a carbonyl group, such as TXB2 during the purification and derivatization steps of biological materials, methyl acetate was used in place of methyl formate as an eluant for Sep-Pak C18 purification.Normal human embryonic lung fibroblasts W138 (5.63 × 105 cells in a log phase) produced: PGA2 15.28, PGB2 13.48, PGD2 7.95, PGE1 2.62, PGE2 177.76, PGF2α 25.14, 6-oxo-PGF1α 27.33 and TXB2 61.00 pmol in 10 ml of Eagle minimal essential medium.
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    Measurement of urinary lactic, 3-hydroxybutyric, pyruvic and acetoacetic acids in a single analysis using selected ion monitoring and stable isotope labelling techniques (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 57-62 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sodium borodeuteride treatment of urine expected to have large concentrations of pyruvic and acetoacetic acids produces lactic and 3-hydroxybutyric acids labelled with deuterium. Mass fragmentographic techniques applied to the trimethylsilyated extract of the urine spiked with more extensively labelled analogues as internal standards permit the reliable determination of lactic, pyruvic, 3-hydroxybutyric and acetoacetic acids in a single analysis.
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    Characterization of trichothecenes by ammonia chemical ionization and tandem mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 79-87 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ammonia and deuterated ammonia chemical ionization (CI) mass spectra and collisionally activated dissociation (CAD) mass spectra of ammonium adduct ions are presented for ten trichothecenes. The samples were introduced by direct exposure probe. Effects of ion source temperature and pressure on the ammonia CI gas plasma and the formation of the ammonium adduct ion were studied. The CI conditions were optimized to produce a maximal yield for the ammonium adduct ion of trichothecenes, i.e. the parent ion for tandem mass spectral analysis. Besides source temperature and pressure, proton affinity and the stability of the ammonium adduct ion affect the relative abundance ratio of [M + H]+:[M + NH4]+ in ammonia CI and CAD mass spectra. The ratio [M + H]+:[M + NH4]+, and hence the stability of the ammonium adduct ion, are largely determined by the functional groups (hydroxy, carbonyl, acetoxy, and isovaleroyloxy) and their location in the trichothecene nucleus. The most abundant fragment ions in the ammonia CI spectra and the most abundant daughter ions in the CAD spectra of the ammonium adduct ions are formed by the losses of ammonia and functional groups as neutrals in various combinations.
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    The application of gas chromatographic/mass spectrometric techniques to spin trapping. Conversion of α-phenyl N-tert-butyl nitrone (PBN) spin adducts to stable trimethylsilylated derivatives (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 111-116 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of an aminoxyl and the corresponding hydroxylamine with silylating agents is studied in detail. The gas chromatographic/mass spectrometric analysis of the products is consistent with the production of an unsaturated product when an alkyl group with exchangeable hydrogens is attached to the nitrone group. The structure of this compound is confirmed by deuteration. It is concluded that aminoxyls themselves do not derivatize wth silylating agents.
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    Gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandins (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 129-138 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/trimethylsilyl ether derivatives of prostaglandin F2α and methyl ester/methoxime/trimethylsilyl ether derivatives of prostaglandin E2, prostaglandin D2, 6-oxo-prostaglandin F1α and 2,3-dinor-6-oxo-prostaglandin F1α are presented. Most of the prostaglandins studied have additionally been 2H-labelled at different sites in order to assign the corresponding fragment ions. Collisionally activated decomposition mass spectra of the most intense parent ions in the high-mass region were taken. High-intensity, prostaglandin-characteristic daughter fragments will allow a reliable quantification of prostaglandins in biological fluids and a reduction of sample clean-up.
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    A gas chromatographic/mass spectrometric assay for catechol estrogens in microsomal incubations: Comparison with a radiometric assay (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 157-161 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic/mass spectrometric assay for quantifying two catechol estrogens, 2-hydroxyestradiol and 4-hydroxyestradiol, in microsomal preparations is described. The assay employs deuterium-labeled analogs of the catechol estrogens as internal standards and permits quantification of catechol estrogens, in microsomal incubations, at low (1-2) μM concentrations. The compounds are analyzed as their trimethylsilyl derivatives following separation by capillary gas chromatography.
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    Electron capture negative ion chemical ionization analysis of arachidonic acid (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 175-178 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A highly sensitive (subpicomole level) and structural specific method for the analysis of arachidonic acid esterified to complex glycerophospholipids has been developed using combined capillary gas chromatography and mass spectrometry. The methodology is based upon the formation of the pentafluorobenzyl ester of arachidonic acid, which is efficiently ionized using electron capture negative ion chemical ionization conditions to yield an abundant carboxylate anion at m/z 301. Quantification is carried out following hydrolysis of the complex glycerophospholipid in the presence of a known amount of (2H8) araachidonic acid. The use of this method is illustrated by the quantification of arachidonic acid within the glycerophospholipid classes isolated from resident peritoneal macrophage cells isolated from HS mice.
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    URL: http://dx.doi.org/10.1002/bms.1200150309
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    Mass spectral investigations on trichothecene mycotoxins. V. Direct analysis of satratoxins by tandem mass spectrometric techniques (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 185-191 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Under chemical ionization conditions, satratoxins preferentially produce negatively charged molecular ions (M-·) over the positively charged protonated molecules. Collisionally activated dissociation of the M-· ions resulted in daughter ions and neutral losses which were characteristic of the macrocyclic ester bridges. Direct tandem mass spectrometric methods of analyses wee developed and applied for the detection and quantification of satratoxins in Stachybotrys atra fermentation broths. Minimum detectable levels for satratoxin standards were 5 pg. A synthetically modified macrocyclic trichothecene, 8-ketoverrucarin A, was used as an internal standard for the quantification of satratoxins in fermentation samples.
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    URL: http://dx.doi.org/10.1002/bms.1200150402
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    Thermospray liquid chromatography tandem mass spectrometry: Application to the elucidation of zolpidem metabolismThis work was presented in part at the 4th Symposium on Liquid Chromatography/Mass Spectrometry and Mass Spectrometry/Mass Spectrometry, Montreux (Switzerland), October 22-24, 1986. (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 223-228 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper discusses the possible advantages of thermospray liquid chromatography/tandem mass spectrometry LC/MS/MS for metabolic mapping. The technique was applied to the study of the metabolism of zolpidem, a new hypnotic with an imidazo-pyridine moiety. When compared to other chromatographic/mass spectrometric-based techniques, reversed phase high-performance liquid chromatography coupled with thermospray LC/MS/MS appears to be the fastest method available today for elucidation of unknown metabolic structures, since it allows identification by direct injection of concentrated urine. However, it was noted during the thermospray process that loss of formaldehyde from a hydroxymethyl amide metabolite occurred. This degradation was not observed when this metabolite was analysed by gas chromatography/mass spectrometry following trimethylsilylation.
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    URL: http://dx.doi.org/10.1002/bms.1200150406
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    Fast atom bombardment mass spectrometry of high-molecular-weight fraction of porphyrin-based photodynamic therapy drugs (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 257-263 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photodynamic therapy (PDT) involves the treatment of tumor tissue with a photosensitizer and light to effect the delineation and/or eradication of the tumor. PDT is a two step process: (1) incorporation of photosensitizer into the cell where it must be retained by tumors in vivo; and (2) illumination of the tumor cell with light to effect cell death. Hematoporphyrin derivative (HPD) is a complex mixture of porphyrins currently used for PDT in the clinical setting. Hematoporphyrin-based oligomers of up to five subunits were determined using fast atom bombardment mass spectrometry of the high-molecular-weight fraction of the drug. Reduction of this fraction with LiAlH4 permitted determination of the covalent bond linking the monomers in these oligoporphyrins. Application of these analytical procedures to the determination of the composition of different preparations of HPD will be described.
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    (18O)quinolinic acid: Its esterification without back exchange for use as internal standard in the quantification of brain and CSF quinolinic acid (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 291-293 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the process of developing a high-sensitivity negative chemical ionization gas chromatographic/mass spectrometric assay for brain and cerebrospinal fluid (CSF) levels of quinolinic acid (QUIN, 2,3-pyridine dicarboxylic acid), (18O4)QUIN was prepared. Its properties as an internal standard were compared with those of the structural isomer 2,4-pyridine decarboxylic acid (2,4-PDC) previously used by others. All oxygen atoms in QUIN were labeled by heating in 3N HCl/(18O)water for 48 h at 80°C. Back-exchange of (18O4)QUIN was prevented during derivatization to an electron-capturing dihexafluoropropanol ester by using trifluoroacetylimidazole as catalyst instead of perfluroacyl anhydrides. When mixtures of QUIN and (18O4)QUIN and/or 2,4-PDC were followed through a procedure to isolate and quantify brain and CSF QUIN, the variability in the ratio of QUIN:2,4-PDC was greater than for QUIN:(18O)QUIN. We conclude that (18O)QUIN is the preferred internal standard in gas chromatographic/mass spectrometric quantification of brain and CSF QUIN, and that (18O)-labeled carboxylic acids may be esterified effectively without back-exchange using acylimidazole reagents.
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    252CF plasma desorption mass spectrometry of a polycyclic peptide antibiotic, Nisin (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 305-310 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polycyclic peptide antibiotic, Nisin, has been analysed by plasma desorption mass spectrometry using two different sample preparation techniques and two versions of the commercial plasma desorption mass spectrometer, and a prototype with high resolving power. The spectra obtained allow identification of a major component and two minor analogues. Extensive fragmentation is observed in samples prepared by the electrospray technique, whereas only ions indicating the molecular weight are produced when the sample is adsorbed on nitrocellulose.
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    Measurement of mevalonate in human plasma and urine by multiple selected ion monitoring (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 174-176 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Plasma levels and urinary excretion of mevalonate were reported to be correlated with cholesterol biosynthesis. Evaluation of mevalonate concentration in plasma and urine represents therefore a non-invasive method for studying the modifications of cholesterol synthesis. A method is described here by wich mevalonate in plasma and urine is determined by the selected ion monitoring technique after extraction as mevalonolactone and conversion into the trimethylsilyl ether. Linear responses were obtained in the evaluation of mevalonate added to plasma in the 10-100 ng/ml (r 〉 0.995) and to urine in the 50-1000 ng/ml concentration ranges, respectively. Identity of mevalonate in plasma and urine was confirmed by high-resolution mass spectrometry.
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    Fast atom bombardment of metal-pyochelin complexes: Metastable analysis at constant B/E of zinc-pyochelinMention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 185-191 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fast atom bombardment (FAB) mass spectrometry was used to characterize the pyochelin complexes of iron and zinc. Ferripyochelin readily forms the [M + H]+ and [2M + H]+ ions in a glycerol matrix. The molecular ion was 2.5 fold more abundant when acetic acid was present. Iron was shown to be present in the iron-pyochelin complex as the ferric ion by wet chemical methods. Differentiation between ferric and ferrous ions by FAB was not successful owing to the FAB reducing environment. Ferric ions were reduced by FAB to ferrous ions in the following model salts - ferric chloride, ferric nitrate and ferric sulfate - when dissolved in either glycerol, thioglycerol or the magic bullet matrix. Ferric and ferrous chloride salts gave virtually identical spectra with a glycerol/acetic acid matrix. Zinc-pyochelin readily forms the [M + H]+ and [2M + H]+ ions, but only when acetic acid was present in the glycerol matrix. The FAB mass spectrum of zinc-pyochelin exhibited various fragmentations which can be used in structural analysis. Linked-scan at constant B/E and accurate mass data were used to characterize the fragmentations of the zinc-pyochelin complex. Metastable analysis allowed the fragmentation pathway of zinc-pyochelin to be determined.
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    Electron impact mass spectrometry of BHT and its alteration products (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 207-217 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact (EI) mass spectra of 2,6-di-tert-butyl-4-methylphenol (BHT) and certain of its alteration products are described in detail. Accurate mass measurements confirm the elemental compositions of important fragment ions in the EI spectra. Collisionally activated mass spectra are also used to study fragmentation and suggest common ion structures. The reference spectra provide the basis for identifying various alteration products of BHT by capillary gas chromatography/mass spectrometry (GC/MS) without the necessity of isolating individual components. Application of GC/MS is made to three studies: (i) pyrolysis of hydroperoxy-BHT as a potential pathway to alteration products in food; (ii) GC/MS pyrolysis of hydroperoxy-BHT as a model study; and (iii) alteration of BHT in ethanol/water as a food-simulating solvent.
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    Fast atom bombardment mass spectrometry of the D-aldohexoses and some deoxyaldohexoses (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 363-372 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The MI and CA spectra of selected positive and negative ions generated by fast atom bombardment (FAB) of the stereoisomeric aldohexoses can be used to differentiate among these isomers, without prior derivatization or addition of other substances. The main fragmentation routes were traced and compared to those of some 2- and 6-deoxyaldohexoses, which appeared to be suitable model compounds. In both positive and negative ion FAB mass spectrometry, the OH group at the C-2 position plays an important role in the fragmentation reactions of the pseudomolecular [M + glycerol + H]+ and [M - H]- ions.
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    Rapid identification of calbindin-D28k cyanogen bromide peptide fragments by plasma desorption mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 387-393 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chicken intestinal calbindin-D28k is an intracellular protein which is believed to have a fundamental role in vitamin D-mediated transport of calcium. A mapping approach based on 252Cf plasma desorption mass spectrometry (PD mapping) was used to screen the DNA-deduced sequence of calbindin-D28k for sequence changes and posttranslational modifications. In the PD mapping experiment, purified calbindin-D28k was cleaved with cyanogen bromide and the resulting peptides were subjected to PD mass spectrometric analysis either as a mixture or as high-performance liquid chromatography isolated fractions. The DNA-derived primary structure of calbindin-D28k was confirmed by rapid PD mass spectral identification of the CNBr peptide fragments, and the nature of the N-terminal blocking group was readily determined to be an acetyl group. The relatively non-destructive nature of the PD mass spectrometric analysis allowed the mapping of the N-terminal peptide through an additional in situ V8 protease enzymatic reaction.
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    Rapid determination of sequence variations in actinidin isolated from Actinidia chinensis (var. Hayward) using fast atom bombardment mapping mass spectrometry and gas phase microsequencing (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 424-428 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A current limitation in the use of fast atom bombardment (FAB) mass spectrometric mapping of peptide mixtures, derived from enzymic digestion of proteins, is that most of the hydrophilic peptides are not observed. However, it has been demonstrated from previous work that esterification of the peptide mixture results in the detection of almost all peptides in FAB mass spectrometry. This strategy of FAB mapping was applied to the protein actinidin, isolated from an Italian variety of Actinidia chinensis. Two of the 12 tryptic peptides in FAB mass spectrometry did not exhibit molecular ions predicted from the known sequence of actinidin isolated from the New Zealand variety of A. chinensis. The two peptides were isolated by high-performance liquid chromatography, subjected to Staphylococcus aureus V8 protease digestion and sequenced by gas-phase microsequencing. Nine changes in amino acid composition were detected using the rapid and powerful combination of FAB mass spectrometric mapping and gas-phase microsequencing.
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    Studies on anabolic steroids II - gas chromatographic/mass spectrometric characterization of oxandrolone urinary metabolites in manFor Part I see Ref. 1. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 429-438 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism of 17α-methyl-17β-hydroxy-2-oxa-5α-androstan-3-one (oxandrolone) in man has been investigated by gas chromatography/mass spectrometry. After oral administration of a 10 mg dose to man, five metabolites were detected in the free fraction of the urinary samples. Oxandrolone, the major compound excreted in urine, was detected within 72 h after administration. During this period 35.8 and 8.4% of the administered dose was excreted as unchanged oxandrolone and 17-epioxandrolone, respectively. In addition, minute amounts of 16α- and 16β- hydroxyoxandrolone and a δ-hydroxy acid resulting from the hydrolysis of the lactone group of oxandrolone were detected in the urine samples 8-60 h after administration. Furthermore, the susceptibility of oxandrolone to hydrolysis was investigated under several pH conditions. Extraction and fractionation of steroidal metabolites was achieved by using C18 and silica Sep Pak™ chromatography. The mass spectra of the metabolites are presented and major fragmentation pathways discussed.
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    Gas chromatographic and gas chromatographic/tandem mass spectrometric characterization of precursors on the sesterterpene pathway for steroid biosynthesis (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 572-575 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An increasing amount of evidence is accumulating to support the proposal that steroidogenesis can occur by a sesterterpene pathway as well as the cholesterol pathway. Key intermediates on the sesterterpene pathway are 23,24-dinor-5-cholen-3β-ol (guneribol) and some of its metabolites, e.g. 23,24-dinor-4-cholen-3-one (guneribone). It has been reported that these intermediates are biosynthesized and converted to steroid hormones by a range of endocrine tissues in vitro. Monitoring the pentafluorobenzyloxime derivatives by negative ion chemical ionization mass spectrometry in the electron capture mode provided evidence for the presence of guneribone in extracts of bovine testicular and human adrenal tumour tissue. Complementary evidence was obtained from gas chromatographic/tandem mass spectrometric data generated on a triple-quadrupole instrument by monitoring daughter ions (in the multiple ion detection, MID mode) of the molecular anion of derivatized guneribone in both standards and tissue extracts. The present findings that sesterterpene pathway intermediates are present as endogenous compounds in tissue extracts, together with the previously reported radiochemical data, give further support to the sesterterpene pathway hypothesis.
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    Determination of cyclic butylboronate esters of some 1,2- and 2,3-diols in plasma by high-resolution gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 592-597 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A gas chromatographic/mass spectrometric analytical procedure is described to determine glycols in plasma as cyclic butyl boronate esters. The method, involving a pre-deproteinization step, required only 0.25 ml of plasma and a short time (20 min) to react with the derivatizing agent (butyl boronic acid). The gas chromatographic separation on a CP Sil 8 CB silica capillary column coupled to a mass detector assured a complete identification of the compounds. The analytical recoveries (〉95%) with low coefficient of variation (4-11%) assured the feasibility of the method over a concentration range from 5 to 1000 μg ml-1 for each glycol. The lower detection limits, namely 1-5 μg ml-1, confirmed the sensitivity of the method.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180814
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    Isotope labelling of lipids using the Favorsky rearrangement (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 603-612 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of tetradeuterated 10-methylundecanoic acid, dideuterated tetracos-2-enoic acid, (1-14C)pristanic acid and (1-14C)tetracos-2-enoic acid using the Favorsky rearrangement are described. They will be used for studies of long-chain fatty acid metabolism in patients. The positions of isotope labelling were determined by mass spectrometry.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180816
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    Structure analysis of modified oligodeoxyribonucleotides by negative ion fast atom bombardment mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 617-619 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Negative ion fast atom bombardment mass spectrometry is used to verify the sequence of oligodeoxyribonucleotides containing a single modified nucleotide. Both the position in the sequence and the molecular weight of the modified nucleotide can be determined from the 3′ and 5′-phosphate sequence ions which are prominent in the mass spectrum.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180818
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    A comparison of positive ion and negative ion fast atom bombardment mass spectral data for some sulphonyl hydrazones and derivatives (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 620-623 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of sulphonyl hydrazones and derivatives have been synthesized and tested for biological activity as pesticides during the crop protection research programme at the Hatfield Polytechnic. A recent comparative ionization study of some of these compounds using electron impact (EI), fast atom bombardment (FAB) and various chemical ionization methods showed FAB mass spectrometry to be the optimum technique to use in terms of molecular weight information obtained. This study compares the FAB mass spectral data in positive and negative ion mode using an alternating positive and negative ion detection system.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180819
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    Rapid structural analysis of the in vitro and in vivo metabolism of SK&F 95448 by the combined use of thermospray liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 637-644 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermospray liquid chromatography/mass spectrometry (LC/MS) interface has had a major impact on the direct analysis of the metabolic fate of xenobiotics in complex biological media. This paper outlines the rapidity and power of the LC/MS approach, and shows how detailed structural information can be obtained without recourse to individual compound isolation. This provides a great saving in time and effort. The additional specificity of liquid chromatography/tandem mass spectrometry is highlighted in identifying the sites of metabolic transformation. The ability to handle biological samples with little or no clean-up using wide high-performance liquid chromatographic gradients is a key feature of the success of this methodology.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180822
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    Phytochemical studies on the essential oils of species belonging to the Achillea genus by gas chromatography/mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 629-636 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several populations of Achillea species were collected from Hungarian localities. The characteristic composition cf the essential oils of almost 220 populations were determined by gas chromatography/mass spectrometry. The main component of Achillea asplenifolia, A. setacea and A. collina oils is chamazulene, with a molecular mass of 184. The composition of some A. setacea is different: instead of chamazulene it contains a significant amount of farnesene. Oils of A. distans, A. crithmifolia, A. nobilis, A. pannonica and A. ochroleuca contain some different and specific compounds instead of chamazulene. During the analysis of many essential oils, we found some very interesting differences within species originating from another geographical area.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/bms.1200180821
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    Gas chromatography/mass spectrometry and gas chromatography/mass spectrometry/mass spectrometry of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxanes (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 139-142 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron impact mass spectra of methyl ester/methoxime/trimethylsilyl ether derivatives of thromboxane B2 (TxB2) and 2,3-dinor-TxB2 and methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 are presented. Additionally, the derivatives of (2H4)-thromboxanes and methyl ester (2H3)-methoxime/trimethylsilyl ether derivatives of TxB2 and 2,3-dinor-TxB2 and (2H3)-methyl ester/trimethylsilyl ether derivative of 11-dehydro-TxB2 were investigated. Collision-induced dissociation mass spectra of the most intense parent ion in the high-mass region were taken. Collisionally activated decomposition mass spectra of the [C(12)-C(20)]+ ion of TxB2 and 2,3-dinor-TxB2 show an intense but not specific daughter ion, whereas the collison-induced dissociation mass spectrum of the [M - (C(16)-C(20)]+ ion of 11-dehydro-TxB2 results in the formation of numerous daughter ions.
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    URL: http://dx.doi.org/10.1002/bms.1200150304
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    Quantification of urinary 3-hydroxyisovaleric acid using deuterated 3-hydroxyisovaleric acid as internal standard (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 652-656 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deficiency of biotin at the tissue level can be assessed indirectly by measuring the urinary excretion of 3-hydroxyisovaleric acid. This paper describes the application of an improved method of quantifying urinary 3-hydroxyisovaleric acid using unlabeled and uniformly deuterated 3-hydroxyisovaleric acid. These compounds were synthesized by a modification of the lithioacetic acid method for generation of beta-hydroxy acids. Elemental analysis, nuclear magnetic resonance, gas chromatographic and gas chromatographic/mass spectrometric data demonstrated that the compounds are greater than 95% pure. Mass spectrometry confirmed the identity of the unlabeled compound, demonstrated that the deuterated compound is uniformly labeled, and offered insight into the pattern of mass fragmentation. The method for determination of the concentration of 3-hydroxyisovaleric acid in rat urine uses gas chromatographic/mass spectrometric quantification of the di-trimethylsilyl derivative with the deuterated compound as the internal standard. Results provide evidence that this method is more accurate than a previously published method that did not utilize the unlabeled and deuterated standards.
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    URL: http://dx.doi.org/10.1002/bms.1200180903
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    Metabolic dissimilarity between (9,12,12-2H)cortisol and natural cortisol in vivo. Can deuterated cortisol be used for the measurement of the urinary cortisol production rate? (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 662-667 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism of deutrated cortisol (9,12,12,-2H)cortisol, (2H3-F) was compared to that of radioactive cortisol (3H2-F) and natural cortisol, when these three compounds were administered simultaneously to an adrenalectomized piglet. The relative isotope dilution of tritium was determined from the specific activities of the main urinary neutral cortisol metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF), normalized to that of the cortisol mixture administered. To obtain a comparison of the isotope dilution of deuterium in the metabolites THE and THF to that in the cortisol mixture, the three steroids were converted to the common oxidation product 11-oxo-aetiocholanolone, and deivatized to the methoxime-tert-butyl-dimethylsilyl ether. The relative 2H-isotope dilution then was measured by gas chromatography/mass spectrometry. It was found that the specific activity of THE in the cumulative urine collections was similar to that of the cortisol mixture administered; the two-day value was, however, less. The specific activity of THF was slightly but significantly smaller than 1 (∼0.9) at all times. The relative 2H-isotope dilution in THE was slightly but significantly larger than one (∼1.1) at all times, whereas that in the THF was larger than 1.0 at 9 and 32 h or equal to 1.0 at 20 and 47 h of urine collection. When comparing the metabolism of the two tracer cortisol species the quotient of the 3H- and the 2H-isotope dilutions in THE and THF was smaller than 1.0. It can be concluded that (2H3)cortisol may be used for the determination of the cortisol production rate.
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    URL: http://dx.doi.org/10.1002/bms.1200180905
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    Direct analysis of different classes of surfactants in raw materials and in finished detergent formulations by fast atom bombardment mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 673-689 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The characterization of the components of a surfactant mixture is a challenge, since we are dealing with substances inherently difficult to purify or separate by any available chromatographic methods. The results of the present work provide evidence that with fast atom bombardment mass spectrometry it is possible to identify the single constituents of the different clases of tensides - non-ionic, anionic, cationic and amphoteric - directly in the mixture and in detergent formulations (shampoos). The method, which is based on unambiguous molecular weight determination of the single components, allows the definition of the exact distribution of oligomers in the surfactant mixture, and distinction of subtle variations in the detergent composition in finished formulations. The results obtained indicate that this technique is a powerful analytical tool which can be used as a rapid screen test for quality control.
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    URL: http://dx.doi.org/10.1002/bms.1200180907
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    Biotransformation of aliphatic formamides: Metabolites of (±)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide in ratsPresented in part at the 35th ASMS Meeting, Denver, Colorado, May 1987. (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 690-701 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vivo biliary and urinary metabolites of (±)-N-methyl-N-(1-methyl-3,3-diphenylpropyl) formamide (1) from male Wistar rats have been characterized by gas chromatography/mass spectrometry. In urine, non-conjugated metabolites included 1,1-diphenyl-3-butanone (4) and 3-methylamino-1,1, diphenylbutane (7). β-Glucuronidase liberated 4, 1,1-diphenyl-3-butanol (5), 1,1-diphenyl-3-butanone oxime (6), N-hydroxymethyl-N-(1-methyl-3, 3-diphenylpropyl) formamide (3), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone (11), 1-(4-hydroxyphenyl)-1-phenyl-3-butanone oxime (12), N-methyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (8), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone (16), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanol (17), 1-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-butanone oxime (18), N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (14) and N-methyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (13). Most of the carbinolamide (3) decomposed in the gas chromatograph inlet to N-(1-methyl-3,3-diphenylpropyl) formamide (2) unless stabilized as a trimethylsilyl (TMS) derivative. In bile, compounds 1, 2, 3, 5, 6, 11, 12 and 16 were present as non-conjugated metabolites. β-Glucuronidase also liberated N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (9), and all of the previously listed compounds except 7. Trimethylsilylation of the conjugated bile fraction revealed the presence of an additional two compunds: N-hydroxymethyl-N-(1-methyl-3-(4-hydroxyphenyl)-3-phenylpropyl) formamide (10) and N-hydroxymethyl-N-(1-methyl-3-(4-hydroxy-3-methoxyphenyl)-3-phenylpropyl) formamide (15). A stable carbinolamide metabolite standard was synthesized and the mass spectral fragmentations of its TMS derivative studied by tandem mass spectroscopy. This is the first report on stable carbinolamide metabolites of high-molecular-weight formamides.
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    Parent ion spectroscopy in the identification of advanced glycation products (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 713-718 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Advanced glycation products have been investigated by parent ion spectroscopy, employing B2/E = constant linked scans of furoyl ions obtained from hydrolysed glycated albumin and polylysine mixtures, without any extraction procedures. Using such an instrumental approach, together with exact mass measurements and collision spectroscopy, the identification of 2-(2-furoyl)-4-hydroxyl-1H-imidazole and 2-(2-furoyl)-4-carboxy-1H-imidazole among the advanced glycation products has been achieved.
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    Identification of long-chain fatty acids and alcohols from human cerumen by the use of picolinyl and nicotinate esters (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 719-723 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human cerumen was hydrolysed with base and the constituents were examined as trimethylsilyl (TMS), methyl ester/TMS, picolinyl/TMS and nicotinate/TMS derivatives by gas chromatography and gas chromatography/mass spectrometry. A sample was also reacted with osmium tetroxide for double bond location. The major constituents were cholesterol, squalene and several series of long-chain fatty acids and alcohols. These latter compounds had chain lengths of 12-26 carbon atoms and were predominantly either straight-chain saturated or straight-chain unsaturated compounds. Saturated branched-chain acids with methyl groups predominantly on even-numbered carbon atoms were present but were less abundant. Unsaturated, branched-chain acids were also present. The major unsaturated acids contained unsaturation at the delta-6-position or were derived from these acids by chain elongation. The compounds were similar to those found in vernix caseosa. The mass spectra of picolinyl esters were, for the first time, shown to be capable of determining both the position of unsaturation and methyl branching in the same molecule.
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    Tandem mass spectrometry of leucine enkephalin and physalaemin using a hybrid instrument (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 727-732 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Daughter ion mass spectral data of [M + H]+ ions of leucine enkephalin and physalaemin, which were formed by fast atom bombardment, were obtained using an instrument of EBQQ configuration. In the case of leucine enkephalin, experiments were carried out in which the collision energy was varied and the collision gas pressure kept constant and vice versa. The results show that conditions can be established under which seuqence-relevant ions above m/z 200 are formed, as well as under which mainly immonium and acylium type ions are generated. Of possible interest for characterization of unknown peptides, when using hybrid instruments, are the mid-chain cleavage ions, which, at a constant argon gas pressure of 5 × 10-6 mbat, were found to maximize at around 30 eV collision energy. Daughter ion mass spectral data are also presented for [M + H]+ ions of physalaemin (mol. wt 1264). Compared to data obtained for physalaemin on multisector instruments, our results indicate that the formation of mid-chain cleavage ions is clearly enhanced.
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    Characterization of virus infected cell cultures by pyrolysis/direct chemical ionization mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 757-760 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The supernatants of Vero cell cultures after infection with a herpes simplex virus or a poliomyelitis virus as well as a blank were analysed by pyrolysis/direct chemical ionization mass spectrometry (Py/DCI MS). Informative pyrogrammes were obtained and used for characterization of viral proteins by applying pattern recognition methods. Differentiation of viral proteins was evaluated by analysing ‘blind’ samples. Herpes viruses could be classified correctly but the observed differences between the blank and the polio virus supernatants were too small for reliable classification of the polio viruses. Purification of the samples seems to be a prerequisite for further studies. The potential value of Py/DCI MS as a rapid non-invasive diagnostic method for viral meningoencephalitis is stressed.
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    Fast atom bombardment combined with tandem mass spectrometry for analysis of a complex mixture of lipo-oligopeptides from Nocardia rubra cell wallskeletonPart of the results in this paper have been presented at the 36th ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, USA, p. 1285 (1988). (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 761-766 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Experimental variables in fast atom bombardment combined with tandem mass spectrometry based on low-energy collision-induced dissociation have been systematically invetigated in order to optimize parameters for analysis of synthetic lipo-oligopeptides. The parameters studied were matrix, ion polarity, collision gas, collision gas pressure and collision energy. The optimal parameters recommended in this study have been applied to the N-terminal amino acid seuquence determination of lipopeptide obtained from Nocardia rubra cell wall skeleton. Daughter and parent ion experiments with negative ion fast atom bombardment combined with tandem mass spectrometry have proven to be very useful for structure elucidation of a complex mixture of lipo-oligopeptides.
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    URL: http://dx.doi.org/10.1002/bms.1200180920
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    The determination of atmospheric bis (chloromethyl) ether by gas chromatography/tandem mass spectrometry (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 775-779 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The technique of gas chromatography/tandem mass spectrometry is applied to the analysis of bis(chloromethyl) ether in laboratory and production environments. A selected reaction monitoring method is shown to yield superior sensitivity and selectivity to previous methods. A detection limit of ∼1 ppt is established even for chemically complex atmospheres which have proved intractable by previous techniques.
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    Sequence analysis of unprotected tri-deoxyribonucleoside diphosphates by 252Cf-plasma desorption mass spectrometryThis paper is part III of a series ‘252Cf-Plasma Desorption Mass Spectrometry of oligonucleotides’. Part II corresponds to Ref. 12. (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 83-90 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The negative Plasma Desorption Mass Spectra of ten unprotected tri-deoxyribonucleoside diphosphatesHereafter termed tri-deoxyribonucleotides. have been observed and analysed in detail. They all exhibit molecular ions as well as a characteristic fragmentation pattern. The ten trinucleotides selected were chosen in order to understand, in terms of sequence, the main features of the experimental spectra. It is shown that the structure and the sequence of the oligomers can be rapidly and easily derived from their PD Mass Spectrum.
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    Redox reactions occurring during secondary ion mass spectrometry of some heteroanthracycline antitumor antibiotic precursors (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 91-96 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive and negative secondary ion mass spectra of the title compounds were produced by bombardment of solid deposits by 13 and 23 KeV cesium ions, respectively, and analyzed with a time-of-flight mass spectrometer. In addition to familiar protonation and alkali (mainly sodium) ion addition processes observed in the positive ion spectra and proton abstractions in the negative ion spectra (which enable determination of molecular weight) there is evidence from both spectral modes for oxidation-reduction processes in which species such as [M - H]+, [M - H + Na]+. and [M + 1]- are formed. It is argued that these may be formed rapidly from pre-associated molecules during bombardment/ionization rather than as a result of radiation damage. Sodium ion addition is apparently facilitated by the presence of electron pair donor groups, especially if chelation is possible.
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    Isotope effect in negative ion chemical ionization mass spectrometry of deuterium labelled lormetazepam (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 257-261 
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    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This study identified the reason for the poor quantification of Iormetazepam-TMS (1) using negative ion chemical ionization with lormetazepam-1,1,1-2H3-TMS (2) as an internal standard. Mass spectra of lormetazepam and its deuterium labelled compounds determined at various ion source temperatures (100-250°C) gave almost the same behaviour for 1 and lormetazepam-3′,4′,5′,6′-2H4-TMS (3) but a different one for 2, suggesting that the poor quantification was due to an isotope effect. This was confirmed by the findings that the ratios of ion currents of the base peaks of 1 and 3 were independent of the ion source temperature but those of 1 and 2 varied markedly with it. This phenomenon was also observed in the mass fragmentography of the molecular ion, although to a lesser degree than that of the above fragment. In both positive ion chemical ionization and electron impact ionization modes, no isotope effect arose because there was no corresponding fragment to cause the isotope effect.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140603
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    Simple mass spectrometric differentiation of the n-3, n-6 and n-9 series of methylene interrupted polyenoic acids (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 127-129 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described to assign the positional series of methylene interrupted polyenoic acids, in complex mixtures, isolated from hydrolysed lipid extracts. It entails a simple comparison of the intensities of three ions of m/z 108, 150 and 192.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140306
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  • 92
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    Hydrolysis of 1,1·,1″-phosphinothioylidinetrisaziridine (thiotepa) in aqueous solution (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 143-148 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The behaviour of 1,1·,1″-phosphinothioylidinetrisaziridine (thiotepa) in water and aqueous salt solution of various acidity was studied by field ionization mass spectrometry (FI-MS), TLC and potentiometric titration. The rate of thiotepa hydrolysis increased with increasing thiotepa, or sodium chloride concentration, and with decreasing pH. As hydrolysis products of thiotepa, mono- and dichloro derivatives formed in neutral, salt-containing and acidic solution, tepa, and products formed by P—N bond cleavage and release of aziridine have been identified.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140402
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    Qualitative and quantitative analysis of the anthelmintic fenbendazole and its metabolites in biological matrices by direct exposure probe mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 161-165 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methodology for the qualitative and quantitative analysis of the anthelmintic fenbendazole and its metabolites in goat feces using electron impact (EI)/direct exposure probe (DEP)/mass spectrometric (MS) and tandem mass spectrometric (MS/MS) techniques is presented. Analyses were conducted on extracts from spiked feces and feces from animals treated per os with 5 mg fenbendazole/kg, with samples being collected at zero time and at twelve hour intervals for 144 h. The results of the EI/DEP/MS quantitation of these samples are compared to those for the same samples analysed by high pressure liquid chromatography (HPLC). Mass spectral data for fenbendazole and its metabolites are presented and the advantages of the use of EI/DEP/MS and/or DEP/MS/MS over HPLC are discussed. This methodology may be used as a confirmatory method for the HPLC analysis of fenbendazole and its metabolites or may be used as a method in its own right for the rapid qualitative and quantitative analysis of these compounds.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140405
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  • 94
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    Acetylation and pentafluorobenzoylation of lidocaine metabolites in aqueous solution and identification of derivatives by combined gas chromatography/mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 173-182 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Known and possible phenolic and primary and secondary amine metabolites of lidocaine were added to urine from drug-naive rats. These metabolites were derivatized in this aqueous medium by acetylation with acetic anhydride or by pentafluorobenzoylation with pentafluorobenzoyl chloride. The derivatives were simultaneously extracted into an organic solvent. The products were separated by gas chromatography (flame ionization detection for acetates and electron-capture detection for pentafluorobenzoates) and identified by combined gas chromatography/mass spectrometry. Mass spectral fragmentation pathways were readily deduced; diagnostic fragment ions were identified and were valuable for characterization purposes. Structural isomers could be distinguished on the basis of their GC retention times.Extractive derivatization using pentafluorobenzoyl chloride is an attractive analytical procedure for the identification of phenolic and dealkylated metabolites of lidocaine.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140407
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    J. F. J. Todd, editor. Advances in mass spectrometry 1985: Proceedings of the 10th international mass spectrometry conference, Swansea, 9-13th September 1985. John wiley and Sons, in two parts, Part A (pp. 568 + xxxix) and Part B (pp. 1094 + liii) (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 195-195 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140410
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  • 96
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    Determination of prostaglandins, and other metabolites of arachidonic acid by thermospray HPLC/MS using post column derivatization (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 213-220 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray HPLC/MS analysis of the metabolites of arachidonic acid proved to be sensitive and specific. The compounds included were hydroxy-fatty acids (5-HETE, 12-HETE, and 15-HETE) and prostaglandins PGD2, PGE2, PGF2α, PGA2, PGA1, TXB2, and 6-Keto-PGF1α. Thermospray HPLC/MS analysis allows for simultaneous monitoring of each compound without the need for additional sample preparation or derivatization. The thermospray spectra for the metabolites exhibited [M + NH4]+ ions and fragment ions because of sequential loss of equivalents of H2O. HPLC/MS showed detection limits in the 0.5 to 5 ng range when using multiple ion detection for most of the metabolites. Post-column derivatization of these metabolites using trimethylanilinium hydroxide (TMAH) to form the methyl esters is also presented. This derivatization resulted in a gain in ion current by a factor of 3-6 for most compounds while adding potential specificity to the analysis. The thermospray spectra of the derivatives were nearly identical to the spectra of the free acid except the peaks were incremented by 14 daltons due to the methyl ester formation. The derivatization of the carboxylic acid group proved to be complete under thermospray conditions producing the maximum ion current and causing no compromise in operation of the interface.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140504
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    Masthead (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987) 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140601
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    Observation of solvent effects on abundance of polyhydrogen adducts (M + nH)+ in fast atom bombardment mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 247-248 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formation of polyhydrogen adducts of peptide molecules during fast atom bombardment (FAB) mass spectrometry (MS) is shown to be matrix dependent. FAB/MS analyses completed in glycerol solvent produced higher than expected peak intensities at m/z corresponding to (M + 2)+, (M + 3)+, and (M + 4)+ when the contributions of all stable isotopes present in the sample are included. Analysis of the same peptides in thioglycerol by positive or negative ion FAB yielded peak intensity distributions for the protonated molecule which matched those predicted from the natural abundance of stable isotopes. These findings suggest that thioglycerol should be the FAB matrix in analyses of peptides when determination of elemental or isotopic composition is desired.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140509
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    Determination of the empirical formula of peptides by fast atom bombardment mass spectrometry (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 249-256 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for calculating the empirical formulae of peptides from mass spectrometric data is described. Exact mass measurement data and isotopic peak ratios are used to generate a list of potential empirical formulae that fit a given compound within experimental error. The formulae are then analysed by a mathematical algorithm and only those corresponding to chain peptides formed from the basic amino acids are retained. Calculations conducted for typical peptides indicate that the approach may be useful for peptide identification if the experimental values are determined within an acceptable range of errors. Experimental measurements of the exact mass and isotopic peak ratios made using typical peptides demonstrate the feasibility of the approach.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140602
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    Editorial (1987)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 303-303 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200140702
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