ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Analytical Chemistry and Spectroscopy  (7,072)
  • Engineering  (3,321)
  • 1990-1994  (10,393)
Collection
Years
Year
  • 101
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 167-177 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Ray-besed methods have been previously developed for accurately predicting the electromagnetic scattering from cavity interiors that allowed for realistic modelling of complex cavities such as jet engine inlets. An analytic geometric model is developed for bifurcated cavities based on connecting sections of generalized super-ellipse functions. The electromagnetic scattering from such cavities using the ‘shooting and bouncing rays’ (SBR) method is discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 102
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 209-221 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A theoretical analysis has been developed to study the crosstalk in crossed bundles of parallel lines. The model is based on the theory of the coupled transmission lines and the resulting system of differential equations has been solved by means of the finite difference, time-domain (FDTD) method. The frequency response of the network has been achieved by the discrete fourier transform (DFT) algorithm; measurements, performed with a vectorial network analyser, show a good agreement with numerical simulation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 103
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 35-41 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The eigenmodes in electromagnetic cavities, loaded with arbitrarily shaped dielectric materials, are computed by the edge element method. The computation shows that the well known ‘spurious modes’ no longer appear. Formulae are given and verified so that the number of zero eigenvalues, which come from ∇ × H = 0, may be accurately predicted. Formulae for the order and density of the global matrices are given for a rectangular cavity regularly divided into bricks and tetrahedra, allowing an associated comparison between the contrasting edge and nodal element formulations. Comparison of the computed results with available theoretical and previously published data show the edge element approach to be a robust, accurate and effective method.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 104
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 253-265 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A numerical frequence-domain modelling of two-terminal, non-linear microwave circuits is presented. It basically relies on a process allowing the solution of the frequency-domain curcuit harmonic balance equations while accounting for the semiconductor device by means of an accurate numerical macroscopic physical model. In its present state of development, the model allows the study of a single two-terminal device circuit operating in harmonic mode. Its capabilites are illustrated by means of the results of a study devoted to the optimization of the load curcuit configuration of a millimetre-wave avalanche diode frequency multiplier. The influence of the output load impedance level on the circuit output RF performance has been investigated for different input power levels in direct frequency multiplication mode and in the presence of additional circuit tunings at low harmonic rank idler frequencies.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 105
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994) 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 106
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 309-319 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: This paper describes a rigorous and systematic procedure to derive a non-linear distributed FET model that an easily be implemented in CAD routines of simulators based on harmonic balance techniques. The new model is derived from a knowldge of the conventional linear lumped equivalent circuit, from non-linear current sources extracted with pulsed measurements, and from the physical dimensions of the FET.For fundamental and haromonic requencies, the FET is modelled by N identical cells. Each cell is made up of a non-linear two-port section inserted between two linear four-port sections that simulate the coupling and the distributed effects along the electrodes of the FET in the width direction only. This non-linear distributed scaling approach to FET modelling has been applied to the analysis of a submicrometre-gate GaAs FET at Millimetre-wave frequencies, and the results were compared to the non-linear lumped element approach. This approach can be applied to other transistors used in non-linear regions at microwave and millimetre-wave frequencies.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 107
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 375-375 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 108
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. ii 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 109
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 399-405 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Symbolic computational systems introduce some unique features in computational engineering. There have been several papers published on the solution of differential equations under given boundary conditions by symbolic systems. The finite element formalism has received prime attention in the course of development of symbolic computation in engineering. The main idea has been to develop a symbolic FEM package to reduce the burden of manual algebra, eliminate errors introduced by numerical quadrature, and improve the efficiency of element generation.This work discusses a symbolic solution to electromagnetic linear antenna problems. The solution is a method of moments that transforms Pocklington's integral equation to a matrix equation. The symbolic system is used to produce (1) analytical integration, (2) the parametric expression for the input impedance and (3) computational code for forward and reverse problem of the input impedance.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 110
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 419-432 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: This paper presents a new finite element formulation in the Laplace domain for both diffusion and wave equations with applications in the field of electrical engineering. With the aid of congruence transformation of matrices, the finite element equations in the Laplace domain are solved and time-domain results can be obtained through the inverse Laplace transform. In a test problem, good agreement between the numerical results derived with the present method and the analytical solutions has been found. For applications in which only Dirichlet and Neumann boundary conditions are involved, this new finite element approach can be applied and provide both frequency-domain and time-domain results in one run without any timestepping scheme. The limitations of using the congruence transformation in solving propagation problems are also addressed in this paper.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 111
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 7 (1994), S. 433-452 
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A hybrid method obtained as a combination of the coupled-mode method (CMM) and the mode-matching method (MMM) is developed and applied in the analysis of multiple dielectric and magnetic discontinuities in rectangular waveguides. As both are moment methods, some kind of truncation has to be carried out in the computer implementation. It is shown that selection of a different number of modes in the two methods is not necessary, unless low-permittivity meida inside the waveguide are considered. As a consequence, the procedure for slecting the number of basis functions is only done in one of the methods. Numerical examples are presented showing the behaviour of the method and the proofs of convergence. Examples are included illustrating the power of this hybrid technique, especially in relation to non-reciprocal structures containing magnetized ferrites.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 112
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 15-19 
    ISSN: 0935-6304
    Keywords: HPLC ; Surfactants ; Sorbitan esters ; Span ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sorbitan ester surfactants are very complicated mixtures. An improved and simple reversed phase high performance liquid chroma tographic (HPLC) method employing a C18 column has been developed for the rapid separation of sorbitan ester surfactants and the quantitative determination of the distribution of sorbitan mono-, di-, tri-, and tetraester fractions. The sorbitan ester distribution of the six Span and Arlacel surfactants studied was calculated using relative response factors obtained from analysis of pure glycerides of fatty acids. The effects of mobile phase composition on the accuracy and reliability of the distribution values calculated for the sorbitan esters were investigated.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 113
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 22-24 
    ISSN: 0935-6304
    Keywords: High resolution gas chromatography, HRGC ; Sulfur chemiluminescence detection (SCD) ; Sulfur gases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three different types of SCD combustion source have been evaluated for use in the chromatographic analysis of atmospheric sulfur compounds. The conventional FID source and the newer inverted burner source were found to be less sensitive and less stable than the flameless design. Overall, the flameless source was superior for use with HRGC-SCD.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 114
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 115
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 116
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 53-55 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 117
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 49-50 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Automated injection ; Solvent venting ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 118
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 119
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography (SFC) ; Edible oils ; Traditional Chinese medicines ; Characterization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A home-made supercritical fluid chromatograph fitted with a capillary micropacked column and equipped with FID detection has been used to separate the components of silicone DC-200, beeswax, tea oil, cod-liver oil, rancid butter, and several traditional Chinese medicines such as Honghua oil, Jiuxin oil, and Wanhua oil.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 120
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 91-94 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Thermal cold trapping (TCT) ; Volatile compounds ; Experimental design ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A central composite design has been used to improve the extraction performance of a dynamic headspace method; extraction yield was evaluated on a homogeneous sample of cheese powder. The volatile compounds were stripped from the sample with nitrogen and adsorbed on a Tenax trap, analysis being performed with a thermal cold trapping injector connected directly to a capillary GC. Three variables (sample temperature, extraction time, and nitrogen flow rate) were investigated, and a quadratic model with interactions was postulated. Twenty experiments was performed, each producing five responses. It was shown that the best conditions for the extraction procedure were those characterized by the highest values of the three variables investigated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 121
    ISSN: 0935-6304
    Keywords: Capillary SFC ; Solid phase extraction ; Quantitative analysis ; Salt-water ; Surfactants ; Span surfactants ; Sorbitan esters ; Hydrophilic-lipophilic balance (HLB) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A rapid, simple and quantitative approach to the separation and identification of sorbitan ester surfactants has been developed using capillary supercritical fluid chromatography (SFC). The sorbitan ester surfactants were well separated into five groups: starting materials and mono-, di-, tri-, and tetraesters, with each group consisting of a number of peaks representing different isomers. High purity glycerides of fatty acids were employed to estimate the relative response factors of sorbitan esters, and reliable group-wise integration served for quantitation of the distribution of sorbitan fatty acid esters. A very important parameter, hydrophilic-lipophilic balance (HLB), which describes the hydrophilic and hydrophobic characteristics of surfactants, could be correlated with the distribution of the sorbitan esters. A combination of solid-phase extraction (SPE) and SFC was used to separate, concentrate, and analyze Span-20 from salt-water samples. In comparison with the HPLC method, capillary SFC broadens the scope of the technique to encompass high molecular weight sorbitan polyesters while maintaining high separation efficiency.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 122
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 99-101 
    ISSN: 0935-6304
    Keywords: Capillary zone electrophoresis (CZE) ; Chiral separation ; Separation of enantiomers ; Cyclodextrins ; β-Blockers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 123
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 116-118 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 124
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 119-119 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 125
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 20-21 
    ISSN: 0935-6304
    Keywords: Capillary GC ; GC-MS ; Gorse pyrolytic oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermochemical conversion of biomass produces solid charcoal, gaseous fuels, and condensable oils. Because these oils vary widely in composition depending on the cellulosic feedstock and the operating conditions used, analysis of the oils is necessary in order to determine the best ways of utilizing or disposing of them. The major components of the organic oil from pyrolysis of gorse have been characterized by capillary gas chromatography - mass spectrometry. A qualitative study of the aqueous oil from the same source has also been attempted.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 126
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 25-30 
    ISSN: 0935-6304
    Keywords: GC ; Dynamic headspace analysis ; Capillary columns ; Flavor ; Volatile flavor compounds ; Dairy products ; Cheese ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aim of this study was to test the suitability and performance of various stationary phases and column dimensions for dynamic headspace gas chromatography of food aromas. The trials were performed using an aqueous test mixture containing thirty seven volatile flavor components of intense aroma, and a sample of ripe Swiss Emmental cheese.The best performance with both samples was obtained with a capillary column coated with a thick film of polydimethylsiloxane. This column resolved the greatest number of compounds in the cheese sample and resulted in the overlapping of one pair of peaks only from the test mixture. Because of its other advantages, i. e. high capacity owing to its film thickness, and insensitivity to the high moisture content of some samples or traces of oxygen in the carrier gas, the polydimethylsiloxane column appears suitable for the analysis of the volatile and highly polar compounds present in complex mixtures such as food aroma.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 127
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 31-36 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Graphitized carbon black ; Carbon layer open tubular columns ; Column polarity ; Retention times prediction ; Programmed temperature GC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polarity of carbon layer open tubular (CLOT) columns coated with a layer of non-porous graphitized carbon black (Carbopack B) modified with an appropriate amount of polar polyglycol liquid phase has been evaluated and compared with that of standard polar (Supelcowax-10) and non-polar (SPB-1) bonded phase open tubular columns. The efficiency and selectivity were measured at various temperatures and the polarity of the columns was evaluated by use of McReynolds' constants and the difference in apparent carbon number, ΔC of linear alkanes and alcohols. The polarity of the CLOT column was found to depend on temperature, and changing the analytical conditions therefore enabled the separation of compounds of different polarity whose reciprocal position and resolution were affected by temperature. The application of calculation methods which enable programmed temperature retention times to be predicted from isothermal data was also found to be possible when the polarity of the CLOT column changes with temperature.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 128
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 47-48 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 129
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 48-48 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 130
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 184-186 
    ISSN: 0935-6304
    Keywords: Chiral capillary GC ; Linalyl acetate ; Bergamot ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 131
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 132
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 197-202 
    ISSN: 0935-6304
    Keywords: GC and GC-MS ; HPLC ; SFC ; TLC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Practically all the conventional chromatographic techniques are used in the characterization of the highly complex mixtures of organic compounds occurring in fuels, heavy fractions, and crude oils. This paper surveys the techniques employed for class determination, preparative fractionation of the main classes, and determination of subgroups after class fractionation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 133
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 217-222 
    ISSN: 0935-6304
    Keywords: Size exclusion chromatography ; Gas chromatography - atomic emission detection ; Sample pretreatment ; Metalloporphyrins ; Crude oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Size exclusion chromatography (SEC) has been demonstrated to be an effective and reproducible sample pretreatment procedure for removal of heavy oil matrices prior to GC-AED analysis of metalloporphyrins, and for the resolution of volatile metal species into clean and defined fractions. This paper also discusses the results obtained by SEC for determination of the distribution of metallopor-phyrins in crude oils and the correlation between total metal, metal-loporphyrin, and total distillable metal content.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 134
    ISSN: 0935-6304
    Keywords: Nitrogen compounds ; Alkylcarbazoles ; Analytical TLC ; Oil migration ; Crude oils ; Petroleum source rocks ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results are reported of a range of laboratory chromatographic fractionation experiments with synthetic model compounds and a petroleum pyrrolic nitrogen fraction. Reversed phase separation of pyrrolic nitrogen compounds was governed mainly by the number of carbon atoms in the molecule, with little selectivity toward different positional isomers, whereas normal phase separation of the compounds could be explained in terms of steric effects related to alkylation position. Comparison of experimental results from model compounds with observations made previously using sets of natural samples taken from sedimentary basins clearly suggests adsorptive interactions between organic and mineral phases are involved in the compositional fractionation of pyrrolic nitrogen compounds in petroleum during migration. Detailed studies of the effects of petroleum migration on the molecular distribution of petroleum pyrrolic nitrogen compounds may provide useful, quantifiable, migration-related geochemical parameters.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 135
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 245-250 
    ISSN: 0935-6304
    Keywords: Fischer-Tropsch waters ; Alcohols in water ; Carboxylic acids in water ; Aldehydes in water ; Ketones in water ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes a quantitative technique for the determination of organic constituents in Fischer-Tropsch by-product waters. Temperature-programmed gas chromatography on derivatized bonded polar capillary columns provides the required separation that permits reliable quantitation of individual compounds. A preliminary combined gas chromatographic-mass spectrometric survey to identify the components present in Fischer-Tropsch by-product waters is presented. The elution order of 58 identified components is tabulated. Components identified in a typical Fischer-Tropsch by-product water include C1-C9 linear and branched alcohols, C3—C8 ketones, C2—C6 carboxylic acids, and C2—C4 linear aldehydes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 136
    ISSN: 0935-6304
    Keywords: High temperature capillary GC ; SPI injector ; Cold on-column injector ; Paraffin deposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: HTHRGC was found essential for optimizing representative preparation of high molecular weight samples and enabling fingerprinting of heavy fractions of crude oils and associated paraffinic deposits in production pipelines. Laboratory experiments aimed at simulating the process of paraffin deposition could also be easily evaluated. A comparative investigation of the performance of cold on-column and SPI (PTV type) injectors, in conjunction with high temperature capillary columns, for analysis of high molecular weight fractions, was also conducted during the course of this work.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 271-276 
    ISSN: 0935-6304
    Keywords: High boiling petroleum fractions ; Polar petroleum compounds ; Compound class separation ; Normal phase HPLC ; On-line LC-MS ; Low voltage electron-impact ionization ; High resolution mass spectrometry ; Deuterated ammonia chemical ionization ; ‘Neutral’ and ‘basic’ nitrogen fractions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatography on Attapulgus clay and on silicic acid has been used to isolate ‘neutral’ and ‘basic’ nitrogen fractions from the 650-1050 °F distillate of an off-shore Californian crude oil. These polar compounds were subjected to on-line liquid chromatography - mass spectrometric (LC-MS) analysis using low voltage electron-impact ionization high resolution mass spectrometry (LVEI HRMS) and deuterated ammonia chemical ionization (ND3 Cl) to determine the molecules' elemental composition and number of exchangeable hydrogen atoms. On-line separation of heavy oils into saturated, 1-4 ring aromatic, and polar compounds was performed by normal phase high performance liquid chromatography (HPLC) on a dinitroanilinopropyl (DNAP) silica column.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 138
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 212-216 
    ISSN: 0935-6304
    Keywords: SFE ; SFC ; Hydrocarbon group separation ; Polynuclear aromatic hydrocarbons ; Total petroleum hydrocarbons ; Simulated distillation ; Polymer additives ; Sulfur chemiluminescence detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of supercritical fluid technology for sample preparation and analysis in the petroleum industry will be described using various examples including: separation of petroleum fuels into hydrocarbon classes, determination of polynuclear aromatic hydrocarbon in soils and petroleum fuels, characterization of fuel-contaminated soil, assessment of fuel boiling point distribution, determination of polymer additives, and characterization of shale rock and drilling mud.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 139
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 223-229 
    ISSN: 0935-6304
    Keywords: Atomic emission detection ; High temperature GC ; GC-AED ; Microwave-induced plasma ; Metalloporphyrins ; Selective detection of metals ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High temperature gas chromatography-atomic emission spectroscopy is used for the detection of vanadyl, nickel, and iron porphyrins in crude oils. The operational variables are investigated with regard to the effects on performance in high temperature GC-AED. Under optimal conditions, the method provides charactersitic metal distributions for oils from different sources. The method is also advantageous in the study of decomposition of petroleum metal species. Several crude oils were analyzed for the content of the distillable metals in comparison with total metals as determined by a direct spectroscopic method.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 140
    ISSN: 0935-6304
    Keywords: Enantioselective GC ; Sesquiterpene hydrocarbons ; Cyclodextrin derivatives ; Essential oils ; Liverworts ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of sesquiterpene hydrocarbons commonly occurring in essential oils has been prepared as racemic mixtures by chemical synthesis. Preparative gas chromatography with selectively per-O-alkylated cyclodextrins has been employed for the isolation of enantiomeric mixtures or pure enantiomers from the essential oils of higher plants and liverworts (Hepaticae). The enantiomers of α-curcumene, α- and β-bisabolene, β-elemene, δ-elemene, α-copaene, δ-cadinene, cis- and trans-calamenene, and bicyclogermacrene could be resolved by enantioselective gas chromatography on capillary columns coated with cyclodextrin derivatives. The enantiomeric composition of these sesquiterpene hydrocarbons in various essential oils was determined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 141
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 335-338 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Specific detectors ; ECD:NPD response ratio ; ECD:FPD response ratio ; Retention indices ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ratio of the responses of two different specific detectors to a single compound has, when used in conjunction with the compound's retention index, been investigated as an identification criterion for the compound. The ECD:NPD and ECD:FPD response ratios have been used for the identification of some pesticides. Analyses were performed with a single column - dual parallel detection - personal computer system.The reliability of the detector response ratio (DRR) was demonstrated by the consistency of detector response with time, and the influence of the quantity of analyte and of the chromatographic operating conditions. These factors were selected in the expectation that the technique could be used for routine trace analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 142
    ISSN: 0935-6304
    Keywords: Multidimensional enantioselective GC ; Stable atropisomeric polychlorinated biphenyls (PCBs) ; Chirasil-Dex ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 143
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 354-354 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 144
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 369-369 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 145
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 407-410 
    ISSN: 0935-6304
    Keywords: High resolution capillary GC (HRGC) ; Coupled GC-GC-MS ; Hydrocarbon distillate ; Alkylbenzenes ; Alkenylbenzenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes the use of multidimensional capillary gas chromatography for analysis of individual components in a C9—C10 aromatic hydrocarbon pyrolysis distillate containing substantial amounts of aromatic olefins. By coupling this GC-GC system on-line to a mass spectrometer difficulties in identifying overlapping compounds were overcome. No coelution of different types of compound was observed, but a few isomeric compounds such as methylstyrenes were poorly separated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 146
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 411-414 
    ISSN: 0935-6304
    Keywords: Size exclusion chromatography ; Gas chromatography ; Coupled LC-GC ; Cleanup and analysis ; Automation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fully automated on-line sample cleanup system based on the coupling of size exclusion chromatography to high resolution gas chromatography is described. The transfer technique employed is based on fully concurrent solvent evaporation using a loop-type interface, early vapor exit and co-solvent trapping. Optimization of the LC-GC transfer was done visually via an all-glass oven door. To circumvent the problem of mixing within the injection loop, an adaptation was made to the standard loop-type interface. The determination of a series of additives in a polymer matrix is presented as one example of the vast range of applications opened up by this technique.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 147
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 325-334 
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Repeatability of electroosmotic flow ; Silica capillary tubes ; Column pretreatment ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of a number of factors, such as the nature of the buffer, the presence of additives therein, the manufacturing conditions, and the pretreatment of the capillary, on the magnitude and repeatability of the electroosmotic flow (EOF) in silica capillary tubes has been investigated. It was established that the nature of the buffer plays the most significant role in respect of the stability and magnitude of EOF, whereas the conditions used for manufacture and pretreatment of the tubing are less important. The EOF obtained using buffers consisting of tris(hydroxymethyl)aminomethane and ethylenediamine was more repeatable than that obtained using pure phosphate buffers. Buffer additives such as sodium dodecylsulfate, 1-butanol, sodium salts of 1-pentanesulfonic acid and 1-heptanesulfonic acid, altered the magnitude of the EOF only, not its repeatability.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 148
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 343-346 
    ISSN: 0935-6304
    Keywords: High performance thin layer chromatography ; Platinum metal 8-hydroxyquinolinates ; Polar stationary phases ; Retention, effect of mobile phase ; Sample preparation ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High performance thin layer chromatography has been used to separate all the platinum metal 8-hydroxyquinolinates on polar stationary phases. The dependence of Rf values on the composition of mobile phases prepared from chloroform - tetrahydrofuran or chloroform - alcohol mixtures has been investigated. Retention was found to be partially dependent on alcohol chain length in chloroform - alcohol systems. The results obtained from TLC are dependent on the method of sample preparation used for the analyte.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 149
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Atomic emission detector ; Organotin compounds ; Organolead compounds ; Organomercury compounds ; Grignard derivatization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As part of a continuing evaluation of new analytical and sample preparation techniques conducted by the US Environmental Protection Agency (EPA), the use of capillary gas chromatography with atomic emission detection (GC-AED) for the simultaneous determination of organotin, organolead, and organomercury compounds in environmental samples was investigated. Pentylmagnesium bromide was used to pentylate ionic organotin, organolead, and organomercury compounds; the pentyl derivatives were then separated by GC and determined by AED. Several important GC-AED parameters, including the type of injector inlet, carrier gas flow rate, and helium make-up gas flow rate, were optimized for the simultaneous determination of these organometallic compounds. Their minimum detectable concentrations were approximately 1.0 to 2.5 ng/mL using a 0.5-μL on-column injection. The calibration curves exhibited good linearity between 2.5 and 2500 ng/mL for organotin and organolead compounds, and between 2.5 and 10000 ng/mL for organomercury compounds.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 150
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 549-552 
    ISSN: 0935-6304
    Keywords: GC/MS ; Crude oils ; Monoaromatic steroids ; Triaromatic steroids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Series of C-ring monoaromatic steroid hydrocarbons (C21, C22, C27 — C29) and triaromatic steroid hydrocarbons (C20, C21, C26 — C28) have been recognized in the aromatic hydrocarbon fraction of Alamein crude oil from the western desert, Egypt. Detection of these compounds were based on mass fragmentography of the key ions m/z 253 and m/z 231 and comparison of the mass spectra and relative retention times with literature data. The predominance of the C29 monoaromatic steroids and C28 triaromatic steroids provide further evidence for a land plant origin of Alamein oil. The results substantiate previous evidence of the occurrence of an aromatization process with increasing maturation and indicate a moderate maturity level for Alamein oil.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 151
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 556-556 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 152
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 559-560 
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Scutellariae Radix ; Flavonoids determination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 567-568 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 154
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 593-596 
    ISSN: 0935-6304
    Keywords: High Temperature Gas Chromatography (HTGC) ; Bis(trimethylsilyl)trifluoroacetamide ; Ethoxylated alcohols ; Ethoxylated alcohol sulfates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conversion of ethoxylated alcohols to trimethylsilyl derivatives and subsequent high temperature gas chromatography allowed for the determination of alkyl chain distribution, mole average degree of ethoxylation and weight percent distribution of several commercial mixtures. Repetitive derivatizations and analyses of a mixture with a vendor specified mole average degree of ethoxylation of 3.0 (Neodol 23-3), yielded an experimental result of 2.93 ± 0.05 (n = 6). Mixtures with different alkyl chain distributions and higher degrees of ethoxylation provided similar accuracy. Extension of the method to the analysis of ethoxylated alcohol sulfate raw materials and ethoxylated alcohol sulfates in dishwashing liquids is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 156
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 607-608 
    ISSN: 0935-6304
    Keywords: Ion Chromatography, IC ; Interference ; Fluoride ; Carbonate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 157
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 609-612 
    ISSN: 0935-6304
    Keywords: Capillary zone electrophoresis (CZE) ; Chiral separation ; Separation of enantiomers ; Acidic chiral compounds ; Dextrins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 158
    ISSN: 0935-6304
    Keywords: Crude oils ; Organic sulfur ; Desulfurization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five crude oils with varying sulfur contents (0.1 - 4.7%) were characterized on a molecular level for organically-bound sulfur. Aromatic fractions were analyzed by GC-(MS) and asphaltene and polar fractions were analyzed by flash pyrolysis-GC-(MS). The polar fractions were also desulfurized with Raney Ni and the hydrocarbons formed were analyzed by GC-MS. Major sulfur compounds in the aromatic fractions were identified as alkylbenzo- and alkyldiben-zothiophenes. The flash pyrolyzates of the asphaltene contained alkylthiophenes and alkylbenzothiophenes as major compounds, depending on the thermal maturity of the oil. Generally, the sulfur-rich crude oils contained relatively more sulfur compounds. The flash pyrolyzates of polar fractions contained a variety of sulfur compounds (alkylthiolanes, alkylthianes, terpenoid sulfides, alkylbenzothiophenes) with substantial differences between different crude oils. Raney Ni desulfurization of the polar fraction yielded hydrocarbons dominated by n-alkanes, but isoprenoid alkanes, n-alkylcyclohexanes, mid-chain methylalkanes, tricyclic terpanes, hopanes and steranes were also present. These hydrocarbons show a potential to fingerprint crude oils since their distribution patterns are more characteristic than those of the hydrocarbons present in the saturated hydrocarbon fraction.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 159
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 537-542 
    ISSN: 0935-6304
    Keywords: Metal-ammonia complexes ; Electroosmosis ; Field strength ; Diuretics ; Resolution ; Capillary length ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The counter ion in CZE separation systems affects resolution, effective field strength and electroosmosis. Alkali metals (lithium, sodium, potassium, and cesium), the ammonium ion, and several complexes of metals with ammonia ([Ag(NH3)2]+, [Cu(NH3)4]2+, [Zn(NH3)4]2+, [Cd(NH3)4]2+, [Ni(NH3)6]2+, and [Co(NH3)6]2+) have been studied for their effect on the separation of diuretics. With the alkali metals the electroosmotic flow velocity decreased and the effective field strength and resolution increased as the hydrated radius of the alkali metal decreased.All the metal-ammonia complexes except that with silver greatly reduced the electroosmotic flow velocity (Veo) and had only a slight effect on the effective field strength (Eeff). Because these complexes had a negligible effect on the ionic strength of the buffer, they enabled high separating power to be maintained during the separation, and hence the use of more energy in the separation system. This yielded better resolution of the compounds, but the analysis time was then compromised.A simultaneous reduction in capillary length and Veo while maintaining the high voltage enabled increased resolution without an increase in analysis time. The ability to control Veo by adding small concentrations (〈 100 μM) of metal complexes to the buffer solution makes it possible to adjust the analysis time and capillary length independently while employing high separation power.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 160
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 543-548 
    ISSN: 0935-6304
    Keywords: GC-FTIR-MS ; Polyunsaturated fatty acids ; Methyl esters ; Oxazolines ; cis/trans isomers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Identification of cis/trans isomers of unsaturated fatty acids cannot usually be achieved by GC-MS (gas chromatography-mass spectrometry) without reference substances. In this study a GC-FTIR-MS system (gas chromatography-Fourier transform-mass spectrometry) was used to identify fatty acid methyl esters (FAMEs) and differentiate between the cis/trans isomers. Besides methyl esters, 2-alkenyl-4,4-dimethyloxazoline derivatives (DMOX), which have been used to locate double bond positions of unsaturated fatty acids, were examined with respect to their suitability for cis/trans differentiation.A combined GC-FTIR-MS system with a wide band (4000-550 cm-1) mercury cadmium telluride (MCT) detector was used in series and parallel to identify 31 reference unsaturated fatty acids, including 7 pairs of cis/trans isomers. Serum samples of healthy persons and commercially available fish oil were analyzed as examples of complex mixtures. Using splitless injection the detection limit for the less sensitive IR detector was 25 ng/μl in case of the weak cis and trans bands.In the FTIR spectra cis/trans isomers were identified by analysis of bands arising from C—H out-of-plane (oop) bending: for both the FAME and DMOX derivatives cis-1,2-disubstituted double bonds give a strong band near 720 cm-1 and the corresponding trans isomers near 967 cm-1. cis Isomers could be identified further by a band at 3012 cm-1. With the combined data of the GC-FTIR-MS system it is now possible to identify polyunsaturated fatty acids with regard to the discrimination of cis/trans isomers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 161
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 557-559 
    ISSN: 0935-6304
    Keywords: Open tubular liquid chromatography (OTLC) ; Inertness ; Protein analysis ; Ultraviolet detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 565-566 
    ISSN: 0935-6304
    Keywords: Micellar electrokinetic chromatography ; Solid phase extraction ; Cycloheximide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 573-576 
    ISSN: 0935-6304
    Keywords: Capillary supercritical fluid chromatography ; Mass spectrometry ; On-line combination ; Polymer additives analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A standard direct introduction capillary interface is used for the SFC-MS analysis of polymer additives. The system is optimized with respect to the position of the restrictor, probe tip temperature, and ion source temperature. El-like charge-exchange spectra are obtained. Cl using ammonia as the reagent gas is used for the quantitative analysis of a real world sample.The experimental capillary SFC-MS spectra obtained show a good similarity with those recorded using the direct insertion probe. The influence of the experimental conditions on the mass spectra obtained is evaluated statistically.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 589-592 
    ISSN: 0935-6304
    Keywords: Silica gel fractionation ; GC-MS ; Industrial waste water analysis ; Biological water treatment ; Tannery waste water ; Dissolved organic compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The separation of the components of complex industrial waste water extracts according to their functional groups has been accomplished by use of small silica gel columns eluted with a hexane - dichloromethane - methanol gradient. The six fractions obtained covered a polarity range from aliphatic fatty acids to (aromatic) polyhydroxy and polyether compounds. Recovery of model compounds was between 75 and 105%.Used prior to GC-MS analysis this fractionation substantially enhances chromatographic resolution and facilitates peak identification. The procedure was exemplarily applied to an extract of anaerobically treated tannery waste water. Phenols, aromatic acids, and aromatic and aliphatic (poly)hydroxy acids, in the low ppm range, were determined as main constituents. Since fractionation extends the range of detection, trace substances such as chlorocresol, dichlorobenzoic acid, mercaptobenzothiazole, and mercaptoacetic acid were also detectable at the ppb level.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 165
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 603-606 
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Lanthanide β-diketonates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chromatographic behaviors of lanthanide chelates of acetylacetone (ACAC), trifluoroacetylacetone (TFA), thenoyltrifluoroacetone (TTA), dipivaloylmethane (THD), 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (FOD), and the thenoyltrifluoroacetonepyridine (TTA·Py) adduct were investigated using packed column supercritical fluid chromatography. Mobile phases consisting of neat and alcohol modified CO2 were used with a phenyl packed stationary phase. Lanthanide complexes of ACAC, THD, and FOD were shown to have better chromatographic performance compared to the corresponding chelates with TFA, TTA, and TTA·Py. In particular, TTA complexes such as Eu(TTA)3 showed characteristic thermal decomposition in the mobile phase at elevated temperature. In addition, retention behavior was found to be a temperature dependent function of volatility and solubility for all chelates studied.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 616-618 
    ISSN: 0935-6304
    Keywords: HPLC ; MEKC ; Diode-array detection ; Flavonoid analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 622-622 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 168
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 643-646 
    ISSN: 0935-6304
    Keywords: High Resolution Capillary GC ; High Resolution GC-MS ; Lemon oil ; Citrus volkameriana ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dependence of the limonene content of lemon (Citrus volkameriana) peel oil on the degree of ripeness of the fruit has been studied by using steam distillation and cold pressing to extract the oils from lemon fruit peel at different stages of maturation (green, greenish-yellow, and yellow-orange peel coloration). Samples of essential oils were analyzed by high resolution GC and GC-MS, using tetradecane as internal standard for quantitation. Forty components were detected; thirty eight were positively identified by comparison of their mass spectra (El, 70 eV) and Kováts retention indexes (determined using a non-logarithmic scale on capillary columns coated with both polar (DB-Wax) and non-polar (DB-1) stationary phases) with those of standards and with data reported in the literature. The limonene concentration reached a maximum level of 79.4% when the fruit was in the intermediate maturation stage characterized by greenish-yellow coloration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 639-642 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Chiral stationary phase ; Chirasil-Val ; Cyclodextrins ; Perfluoroacylation ; Enantiomeric separation ; Amino alcohols ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic amino alcohols have been separated as perfluoroacylated derivatives by gas chromatography using either improved Chirasil-Val or heptakis(2,6-di-O-methyl-3-O-pentyl)-β-cyclodextrin as stationary phase. Using Chirasil-Val all the amino alcohols investigated were separated to baseline (α values between 1.03 and 1.08) whereas only a few amino alcohols were resolved on the modified cyclodextrin column. The enantioselectivity obtained on the latter phase was, however, significantly higher.The separations were performed as trifluoroacetyl, pentafluoropropionyl, and heptafluorobutyryl derivatives and the chiral discrimination observed for the different derivatives was significantly different for both stationary phases.In oder to obtain a better understanding of the separation mechanism, the Gibbs-Helmholtz parameters Δ(R,S)ΔH° and Δ(R,S)ΔS° were determined. The most extraordinary result was obtained for the trifluoroacetyl derivative of allo-threoninol. In addition to the order of elution of the enantiomers being the opposite of that for the other compounds, the separation seems to be entropy controlled (the sign Δ(R,S)ΔH° is positive), i.e. the separation improved at higher temperatures.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 171
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 662-664 
    ISSN: 0935-6304
    Keywords: Capillary GC ; Sorbent cartridge ; Medium-chain fatty acids ; Fatty acid ethyl esters ; Beer analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modification of a procedure by Hage [1] is proposed for the gas chromatographic evaluation of the content of free medium-chain fatty acids and related ethyl esters in beer. The method involves extraction of free fatty acids and ethyl esters by SPE using C18 bonded phase columns, derivatization of free fatty acids and related ethyl esters with diazomethane, and GC analysis using an SP-2340 capillary column. The results obtained have shown the method to be rapid and highly reproducible. The technique has been compared with other methods used for determination of free fatty acids.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 172
    ISSN: 0935-6304
    Keywords: Oxazaphosphorines ; Iphosphamide ; Iphosphamide metabolites ; Electron capture chemical ionization MS ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the determination of the antitumor agent iphosphamide and seven of its metabolites in the plasma of cancer patients by multiple ion monitoring (MIM) GC-MS, mainly using the electron capture chemical ionization mode, of stable methyl and/or trifluoroacetyl derivatives. The metabolites determined were 2- and 3-dechloroethyliphosphamide, 4-ketoiphosphamide, carboxyiphosphamide, iphosphamide mustard, and two previously undetected metabolites, chloroethylamine and 1,3-oxazolidine-2-one.The isolation of the acidic and neutral metabolites was performed by solid phase extraction on to C18 adsorbent at pH 4. The weakly acidic iphosphamide mustard, isolated under these conditions with a yield of ca 50%, was measured as a stable methyltrifluoroacetyl derivative, in contrast to the corresponding phosphoramide mustard of the isomer cyclophosphamide which decomposes during derivatization. Chloroethylamine and 1,3-oxazolidine-2-one were isolated with high yield by liquid extraction with ethyl acetate at pH 10.Selective measurement of several metabolite derivatives with similar retention times was performed by multiple ion monitoring MS of specific ion masses, using a methyl phenyl siloxane capillary column previously employed in the study of cyclophosphamide metabolites. Quantitation of metabolites in patient plasma samples could be performed in the concentration range 3 ng to 20 μg per ml of original plasma.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 759-764 
    ISSN: 0935-6304
    Keywords: Supercrirtical fluid extraction (SFE) ; Modified carbon dioxide in SFE ; Liquid trapping ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A polarity test mix consisting of acetophenone, N,N-dimethylaniline, naphthalene, 2-naphthol, and n-tetracosane was spiked onto sand and extracted with carbon dioxide modified with acetonitrile, methanol, or toluene. The extracts were collected in chloroform, hexane, methanol, or a mixed collection solvent consisting of equal parts chloroform-hexane-methanol. The mixed collection solvent which showed excellent recoveries for pure CO2, had the worst recoveries of all the collection solvents with modified CO2. Overall hexane was the best collection solvent studied for these analytes under these extraction conditions.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 57-57 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 176
    ISSN: 0935-6304
    Keywords: GC-AED ; High boiling PAC ; Peak splitting in discharge tube ; Additional make-up gas ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Peak splitting of high molecular weight polycyclic aromatic compounds originating from the microwave plasma of an atomic emission detector (AED) coupled to a GC has been described and evaluated. The influence of the solute structure, solute concentration, and physical conditions in the AED (such as detector temperature, make-up gas flow, concentration of reagent gases and distance of column end from the plasma) have been studied. An explanation is presented for peak splitting, which is based on an insufficient solute decomposition and solute mass flow in the discharge tube. Modification of the instrument by introduction of additional make-up gas applied through the transfer line has been shown to improve peak shape and solute response.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 177
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 153-159 
    ISSN: 0935-6304
    Keywords: Capillary GC-MS ; Purge and trap GC-MS ; Extraction ; Solid phase extraction ; Fractionation ; Organic contaminants in municipal wastewater ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High resolution capillary gas chromatography-mass spectrometry has been used in combination with various sample preparation methods to analyze a wide range of low molecular weight organic contaminants in municipal wastewaters. Volatile organic compounds were extracted using a purge and trap concentrator connected directly to a wide bore DB-624 capillary column. Because of the high organic load in wastewater samples, this method was preferred to the more sensitive closed loop stripping technique which suffered from competition effects and insufficient adsorbent capacity. Volatile and semi-volatile base/neutral compounds and acids were extracted with dichloromethane at pH 11 and pH 2, respectively, or were recovered using a simultaneous distillation-extraction procedure. Acidic compounds were subsequently derivatized using diazomethane methylation. Both fractions were separated with a 30m DB-5ms capillary column. Specific ionic substances (LAS, NTA, EDTA) were isolated by solid-phase extraction then derivatized with diazomethane (LAS) or acetyl chloride in n-butanol (NTA, EDTA) before GC-MS analysis.This array of techniques enabled the identification of more than 150 organic contaminants in the influent of a municipal wastewater treatment plant in northern suburban Paris. The individual concentrations of these contaminants ranged from 〈 0.1 μg/l to 5.7 mg/l.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 169-173 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 179
    ISSN: 0935-6304
    Keywords: Nonaqueous solvent ; Capillary electrophoresis ; CE-electrospray-mass spectrometry ; Drug metabolism ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 180
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography (CGC) ; Enantioselective separations ; (2,3,6-Tri-O-methyl)cyclodextrins ; Enantiomeric excess determination ; 2,3-Isopropylidene-1,2,3-cyclohexanetriol derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Capillary GC on permethyl α-, β-, and γ-cyclodextrins has been applied to separate and quantify the enantiomers of some 2,3-iso-propylidene-1,2,3-cyclohexanetriol derivatives. Quantitative CGC data are compared to those obtained with chiral shift 1H NMR.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 181
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 98-98 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 182
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 107-108 
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Polyacrylamide ; Hydrophobic interaction ; Electrokinetic chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 183
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 104-106 
    ISSN: 0935-6304
    Keywords: HPLC ; SFC ; Rapid analysis ; Donor - acceptor chromatography ; Acceptor bonded phases ; C60 fullerene ; C70 fullerene ; Higher fullerenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 118-118 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 185
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 186
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 350-352 
    ISSN: 0935-6304
    Keywords: Supercritical fluid extraction ; Supercritical fluid derivatization ; C18 adsorbent ; Capillary GC ; Polar compounds ; Phenoxycarboxylic acids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994) 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 373-389 
    ISSN: 0935-6304
    Keywords: GC ; Natural gas analysis ; Sulfur components ; Selective enrighment ; Sulfur selective detection ; Calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: More stringent environmental regulations as well as higher demands presently being imposed on the sulfur content of natural gas feed-stocks for chemical processes necessitate the development of new analytical procedures for sulfur determination in natural gas. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. The complexity of the natural gas matrix as well as the extremely low concentration levels at which the sulfur species occur make the development of these analytical methods a true challenge. In this review the three steps common for analytical methods for trace analysis in complex matrices, i.e. pretreatment, chromatographic separation, and detection, are discussed in detail. Possible methods for calibration of the system are discussed in the final section.Various techniques to determine sulfur in natural gas are described. Depending on the application, the most suitable system has to be selected. For example, for on-line application in a hazardous area a simple and rugged system is required, i.e. a simple gas chromatograph with a flame photometric detector, while for laboratory application a more complex instrument including preconcentration, column switching, and more exotic detection systems could be more suitable. Therefore it is crucial to define the requirements of the instrument at an early stage and use the information in this review article to develop/select a dedicated instrument/procedure for the problem at hand.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 189
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 398-406 
    ISSN: 0935-6304
    Keywords: High temperature GC ; Pyrolysis ; Hydrocarbons ; Waxes ; High molecular weight hydrocarbons (C40—C100) ; Asphaltenes ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the past two or three decades geochemists have been concerned with the analyses and characterization of compounds, generally hydrocarbons, ranging from C1—C40. Significant amounts of information have resulted from these studies which have been extremely useful in many geochemical and environmental studies. However, in the past two or three years the commercial development and availability of high temperature gas chromatography columns has lead to the investigation of the occurrence and distribution of high molecular weight hydrocarbons (HMWHC), and other compounds, in the carbon number range C40—C100, present in oils, waxes, bitumens and rock extracts. The ability to study these compounds represents a major advance in organic geochemistry. In some samples these compounds may represent the bulk of the organic components but prior to development of the high temperature columns it was impossible to study their distributions.This paper will review advances that have occurred in terms of the application of high temperature gas chromatography (HTGC) to the analyses of fossil fuel samples and discuss the possible origin and significance of these compounds that have been identified. In addition, some of the potential problems involved in the analyses of these compounds will also be discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 190
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Cyclodextrin derivatives ; Polychlorinated pesticides ; Polychlorinated biphenyls (PCBs) ; Pyrethroid insecticides/Allethrin ; Organophosphorus pesticides/Acephate, Malaoxon ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enantiomers of the polychlorinated polycyclic xenobiotics heptachlor, cis- and trans-chlordane, cis- and trans-heptachlorepoxide, oxychlordane, and bromocyclen have been resolved by gas chromatography with selectively substituted cyclodextrins. The order of elution of these compounds and of α-hexachlorocyclohexane (α-HCH) was determined by comparison with enantiomerically enriched reference compounds obtained by preparative enantioselective gas chromatography.A separation of the eight stereoisomers of the pyrethroid insecticide allethrin into seven peaks was achieved. Both trans-diastereomers were separated into their enantiomers and the order of elution could be determined by comparison with commercially available (S)-bioallethrin and trans-bioallethrin. Also one cis-diastereomer was separated, wheras the other cis-isomer could not be resolved. In addition 15 out of 19 stable atropisomeric polychlorinated biphenyls with 5, 6 and 7 chlorine substituents, some chiral organophosphorus pesticides, including acephate and malaoxon and the herbicide bromoacil were separated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 191
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 713-718 
    ISSN: 0935-6304
    Keywords: Electrophoretic capillary chromatography ; Organic modifiers ; Hydrophobic association ; Capacity factors ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Very good separations of non-ionic organic compounds have been achieved by capillary zone electrophoresis (CZE) using a tetrahep-tylammonium salt as an additive in aqueous acetonitrile as solvent. A systematic study was undertaken to determine the effect of experimental parameters on electroosmotic mobility and electro-phoretic mobility. It was found that pH, acetonitrile concentration, and the type and concentration of quaternary ammonium salt are important experimental variables. Under appropriate conditions, the separation window was enlarged and a broad range of electrically neutral organics, including very hydrophobic compounds (e. g. poly-cyclic aromatic hydrocarbons) and fairly hydrophilic compounds were separated in a relatively short time. By adjusting the separation conditions, high resolution CZE of a specific group of neutral organic compounds could be achieved. A method for calculation of capacity factor was proposed and capacity factors for a variety of non-lonic organic compounds were calculated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 729-731 
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Electrospray mass spectrometry ; Sample concentration ; Peptides ; Drug metabolites ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 193
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 739-740 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 194
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 740-740 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 745-748 
    ISSN: 0935-6304
    Keywords: Organomercury compounds ; Capillary GC ; Atomic fluorescence detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of methyl- and ethylmercury (MM and EM) halides in biological and environmental samples is generally performed by gas chromatography with electron capture detection. Tedious sample work-up protocols and poor chromatographic response (using packed columns) have, however, shown the need for the development of new methods in this field.This paper reports a sensitive method, free from these deficiencies, for the determination of methyl- and ethylmercury. The organomercury compounds (MM and EM) are first released from the sample matrix, by the combined action of acidic potassium bromide and cupric ions, and then extracted into dichloromethane. The initial extracts are subjected to thiosulfate clean-up and the organomercury species are isolated as their chloride derivatives by addition of cupric chloride, and subsequent extraction into a small volume of organic solvent. Capillary GC coupled with atomic fluorescence detection provided excellent separation efficiencies for methyl- and ethylmercury and proved to be a very selective and sensitive technique. The absolute detection limit for both MM and EM was found to be 0.2 pg.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 196
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 120-120 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 197
    ISSN: 0935-6304
    Keywords: Two dimensional GC ; Heart cutting ; Retention index monitoring (RIM) ; Two-stage RIM ; GC-MS ; Selected ion monitoring ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two-stage capillary GC with two-stage retention index monitoring is an efficient analytical technique which can be used for detection and determination of small amounts of volatile compounds in complex mixtures of hundreds or thousands of other compounds. The system employs two capillary columns, coated with different stationary phases, connected on-line with the aid of a micro valve; the first column acts as a pre-separating unit from which unresolved fractions of interest are cut (transferred) into another column for final, interference-free separation of the compounds to be determined. This technique has been compared with selected ion monitoring capillary GC-MS using a hydrocarbon mixture as a test sample for comparing resolution, repeatability, and the practical usefulness of the techniques. Results indicate that two-stage capillary GC is very useful for mixtures containing compounds which produce mostly non-specific ions in the MS ion source whereas compounds producing specific ions can be easily analyzed by capillary GC - single ion monitoring MS even if they are not perfectly separated by a single capillary column.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 198
    ISSN: 0935-6304
    Keywords: High resolution capillary GC (HRCGC) ; HRCGC-MS ; Protein amino acids ; Non-protein amino acids ; Amino alcohols ; Hydroxycarboxylic acids ; tert-Butyldimethylsilyl (TBDMS) derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple, single-step derivatization technique is presented for capillary GC-FID and GC-MS separation and identification of common protein and non-protein constituents of natural peptides as their tert-butyldimethylsilyl (TBDMS) derivatives. The tert-butyldimethyl-silylation of more than sixty compounds was accomplished with high yields and a single peak observed for each component. The TBDMS derivatives of both the protein and non-protein substances, moreover, exhibit excellent separation on apolar capillary columns and can be resolved completely using a polydimethylsiloxane or 5 % phenyl polydimethylsiloxane column and, complementarily, a 50 % phenyl polydimethylsiloxane column. Retention data and molar responses of the TBDMS derivatives on the polydimethylsiloxane column are compiled. Direct coupling of the 5 % phenyl polydimethylsiloxane column to an ion trap mass spectrometer enabled fast separation and identification of the investigated components, at nanomole to picomole levels, on the basis of retention and mass spectral data. The general usefulness of the method is demonstrated by research into new biologically active peptides isolated from entomopathogenic fungi.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 199
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 165-168 
    ISSN: 0935-6304
    Keywords: GC-MS ; Quantitation ; Selected fragments ; Sugars ; Carboxylic acids ; Citric acid ; Isocitric acid ; TMS derivatives ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A GC-MS method has been developed for the analysis of the sugar and carboxylic acid content of citrus fruits, including the quantitation of isocitric acid in the presence of a large excess of citric acid. Optimum conditions have been determined for the analysis (from one solution, by one injection, on a 30 m DB-5 column) of the TMS oxime and/or TMS derivatives of sugars and acids obtained from various lemon, grapefruit, and orange samples. Quantitation was based on the monitoring of the total ion current and of selective fragments. The utility of the method has been demonstrated by the determination of isocitric acid in the presence of 10- to 200-fold excess of citric acid.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 200
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 17 (1994), S. 177-179 
    ISSN: 0935-6304
    Keywords: Capillary GC ; High temperature analysis ; Novolac resins ; Epoxy resins ; Retention indices ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...