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  • NDE  (20)
  • Chromatographie, Gas  (17)
  • Springer  (37)
  • American Institute of Physics
  • 2005-2009
  • 1980-1984  (37)
  • 1925-1929
  • 1980  (37)
Collection
Keywords
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  • Springer  (37)
  • American Institute of Physics
Years
  • 2005-2009
  • 1980-1984  (37)
  • 1925-1929
Year
  • 1
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    Journal of nondestructive evaluation 1 (1980), S. 277-286 
    ISSN: 1573-4862
    Keywords: Ultrasonics ; through-transmission ; composite materials ; attenuation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The steady-state amplitude of the output of an ultrasonic through-transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios, the specimen-transducer reflection coefficient, the specimen-transducer phase-shift parameter, and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress-wave reflections are taken into account, and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). Thus, the technique provides a direct method for continuous or intermittent monitoring of through-thickness attenuation of plate structures which may be subject to service structural degradation.
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  • 2
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    Journal of nondestructive evaluation 1 (1980), S. 263-276 
    ISSN: 1573-4862
    Keywords: Ultrasonics ; scattering ; diffraction ; defect characterization ; cracks ; voids ; pattern recognition ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Shape and size are the most important defect characteristics that need to be determined for the reliable prediction of the remaining service lifetime of a defective structure or part. The analytical and supporting experimental results presented in this paper concern a general, pattern recognition-based, ultrasonic defect identification and sizing method. The satellite-pulse technique (SPT) is based on the interpretation, in terms of defect types (shapes) and dimensions, of the separation in time of arrival between the readily detected specularly reflected pulse and its generally ignored tip-diffracted or tangentially scattered “satellite” contained in the received waveform. Calibration procedures were also developed that enable the ultrasonic examiner to read the time scale of the oscilloscope for equivalent crack depth or void diameter as appropriate.
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  • 3
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    Journal of nondestructive evaluation 1 (1980), S. 3-9 
    ISSN: 1573-4862
    Keywords: harmonic generation ; fatigue ; microcracks ; aluminum ; surface acoustic waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Harmonic generation of surface acoustic waves (SAW) is shown to be a useful tool for the detection of the initiation of surface cracks during fatigue of high strength aluminum alloys. A model that relates the length and density of microcracks to the amplitude of a SAW harmonic signal is described, and an associated coefficient of generation efficiency for the second harmonic amplitude is derived. A correlation between experimentally measured harmonic amplitude and remaining fatigue life is then demonstrated, which allows the mean remaining fatigue lifetime to be estimated to within 5% over the last 50% of the fatigue life for an Al 7075 alloy if the cyclic stress amplitude, but not the duration of fatigue, is known.
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  • 4
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    Journal of nondestructive evaluation 1 (1980), S. 11-19 
    ISSN: 1573-4862
    Keywords: ultrasonic diffraction ; fatigue cracks ; crack closure ; crack surfaces ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract This paper describes an ultrasonic diffraction technique for characterizing fatigue cracks. The angular field of energy scattered from a crack tip was computed. Using the theoretically predicted and experimentally verified optimum range of angles, we measured the crack profiles by the ultrasonic diffraction technique. Ultrasonic measurements agreed very well with direct destructive measurements. In addition, fatigue crack closure was detected and information on crack surfaces was obtained.
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  • 5
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    Journal of nondestructive evaluation 1 (1980), S. 21-36 
    ISSN: 1573-4862
    Keywords: ultrasonics ; surface defects ; defect depth ; deconvolution ; correlation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract In previous work by the authors,(1,6) it was demonstrated that the presence of near-surface defects could be detected reliably, even though the defect echo was contained within the near-surface echo. The algorithm consists of examining the variation in the composite (near-surface plus defect) response after it has been deconvolved from a near-surface response known to be defect-free. This paper presents two algorithms that have been developed subsequent to the work presented in ref. (6) for estimating thedepth of a near-surface defect, given that its presence has already been detected. One algorithm uses complex frequency domain techniques, and the other uses time domain analysis. Both procedures operate on the surface-plus-defect signal, using reference signals containing surface-only and defect-only responses. The defect signal is extracted from the composite signal. Defect depth is then computed from the time difference between the centers of the front-surface and extracted defect responses. A mean absolute depth error of 0.015 in. was obtained by applying the algorithms to experimental data containing depths from 0.020 to 0.130 in. below the near-surface.
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  • 6
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    Journal of nondestructive evaluation 1 (1980), S. 37-52 
    ISSN: 1573-4862
    Keywords: failure prediction ; accept/reject decisions ; ceramic materials ; ultrasonics ; fracture ; probabilistic model ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A general probabilistic method for reaching accept/reject decisions and failure prediction based on nondestructive evaluation procedures is described. The method is illustrated for ceramic materials that fail by the activation of microcracks located at void surfaces. The inspection procedure used for the analysis is the long wavelength ultrasonic method. The analysis indicates influences on the decision level and on the false-reject probability of variations in the signal-to-noise ratio and in the preexistent void population. The ultrasonic inspection is shown to exert a relatively minor influence on the false-reject probability, even for low signal-to-noise ratios, low stresses, and a widely dispersed void population, because of the intrinsic variability of the selected failure process. More encouraging results concerning the utility of NDE are anticipated to apply to other failure mechanisms in ceramics.
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  • 7
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    Journal of nondestructive evaluation 1 (1980), S. 53-66 
    ISSN: 1573-4862
    Keywords: ultrasonic transducers ; phased array ; ultrasonic imaging ; impulse response ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The present contribution provides a method for the derivation of analytical near- and far-field expressions for the pressure step-function response of nonuniformly excited ultrasonic transducers modeled as pistons of arbitrary shape in an infinite rigid baffle. Explicit inversion of the Laplace transformed ultrasonic field using Cagniard's idea results in elementary functions or definite integrals of elementary functions, depending on the assumed nonuniform aperture distribution. The basic signal distortion is illustrated in terms of three-dimensional space-time plots of the pressure unit step-function response of a rectangular uniform aperture. The corresponding results for a phased-array transducer are also given. In addition, we investigate the pressure profile on the axis perpendicular to a uniform rectangular piston and its horizontal radiation pattern for different bandwidths of the exciting impulse.
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  • 8
    ISSN: 1573-4862
    Keywords: stress fields ; microstructure ; J integral ; stress intensity factor ; harness acoustic velocity ; acoustic elasticity ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A very precise system for measuring two-dimensional velocity fields in solid samples has been used for nondestructive measurements of both externally applied and residual inhomogeneous stresses in solids,J integrals, stress intensity factors of cracks, and hardness of quenched steel. The longitudinal velocity measurement is based on precise determination of the propagation transit time through the stressed solid specimen using a small diameter, water-coupled acoutic transducer, which is scanned mechanically over the sample. Changes in velocity are then related to changes of stress in the sample by the theory of acoustoelasticity. Similar measurements show a high degree of correlation between longitudinal velocity changes and changes in microstructure in steel samples. Applications to problems of solid mechanics and material science illustrate the utility of this nondestructive measuring technique.
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  • 9
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    Journal of nondestructive evaluation 1 (1980), S. 79-85 
    ISSN: 1573-4862
    Keywords: ultrasonic waves ; EMAT ; surface stress ; NDE ; Green's function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An analysis of the radiation from a body force shows that it is equivalent to the radiation from a series of surface stresses defined by the moments of the body force taken with respect to the depth coordinate. As the body force becomes localized near the surface, the zeroth moment of the force dominates the radiation and is often thought of as an equivalent surface stress. However, under certain conditions, this can vanish, and the other moments must be considered. It is found that, as the order of the moment of a particular force component increases, the resulting radiation patterns alternate between those characteristic of a compressive surface stress and those characteristic of a shear surface stress, which have considerably different angular variations. Results of experiments in the development of EMAT transducers for nondestructive testing that support these results are cited, and important consequences in the design of inspection systems are indicated.
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  • 10
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    Journal of nondestructive evaluation 1 (1980), S. 225-233 
    ISSN: 1573-4862
    Keywords: Acoustic emission ; energy analysis ; composite materials ; strength ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A new technique which uses the output of a true RMS voltmeter to measure the acoustic emission energy output of a transducer is presented. To demonstrate its use in a typical case, this procedure is used to measure acoustic emission energy during tensile tests on [0°/±30°/90°]s glass-epoxy laminate uniaxial and 10° off-axis tensile coupons. The test results were compared with numerical predictions of laminate response and acoustic emission energy. The experiments indicate that acoustic emission energy can be used to indicate the onset of ply and interlaminar failure.
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  • 11
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    Journal of nondestructive evaluation 1 (1980), S. 235-247 
    ISSN: 1573-4862
    Keywords: Ultrasonics ; acoustic waves ; scattering ; diffraction ; defect characterization ; silicon nitride ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The scattering of acoustic waves by different types of spherical defects in a silicon nitride matrix is calculated by using Ying and Truell's scattering theory. The theoretical scattering results are interpreted using a ray tracing approach. Experiments were carried out at a high frequency (150–450 MHz) to characterize defects in silicon nitride. Time and space averaging, Wiener filtering, diffraction, and propagation loss corrections were used to remove the effect of the transducer response and propagation loss in the material from the scattered signal. Our experimental results indicate the presence of a new type of defect in silicon nitride. They give the type and size of voids, cracks, and Si inclusions in good agreement with measurements obtained after sectioning.
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  • 12
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    Journal of nondestructive evaluation 1 (1980), S. 101-109 
    ISSN: 1573-4862
    Keywords: ultrasonic transducers ; NDE ; deconvolution ; signal processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A major objective of quantitative nondestructive evaluation is to formulate defect detection, classification, and sizing algorithms that are insensitive to variations in transducer characteristics, material type, and defect depth. With the data used in this research, ultrasonic signals were found to vary significantly with changes in the transducer and only secondarily with changes in material and depth. It is shown that the method for minimizing signal variations due to transducer and material changes is to deconvolve the test signal with respect to the transducer response from a reference defect in a block of the same material. Since depth variation primarily affects signal amplitude and has minor impact on shape, detection, classification, and sizing, insensitivity to depth is achieved by avoiding the use of amplitude-dependent parameters. The notion of a “standard transducer” is introduced. Its mathematical properties and methods of realization are given. It is shown how the effects of variability from different test transducers can be removed by signal processing. When these procedures are applied to the test transducer, the effect is to cause it to resemble the standard transducer and, thereby, to place all ultrasonic waveforms on a common basis.
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  • 13
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    Journal of nondestructive evaluation 1 (1980), S. 137-148 
    ISSN: 1573-4862
    Keywords: composite material ; ultrasonic velocity ; ultrasonic attenuation ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The ultrasonic group velocity and attenuation were measured as a function of frequency for longitudinal and shear waves in the Hercules epoxy matrix (3501-6) and in the principal directions of the unidirectional Hercules graphite fiber epoxy composite (AS/3501-6). Tests were conducted in the frequency ranges 0.25–14 MHz and 0.5–3 MHz for longitudinal and shear wave modes, respectively. While the attenuation increased with frequency for all wave modes, the group velocity was independent of frequency for all wave modes. In studying the effects of transducer-specimen interface couplant and pressure, it was found that for each transducer, there exists a frequency-dependent “saturation pressure” corresponding to the maximum output amplitude of the signal.
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  • 14
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    Journal of nondestructive evaluation 1 (1980), S. 149-155 
    ISSN: 1573-4862
    Keywords: acoustic emission ; fracture ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The far-field characteristics of the emission from a theoretical model for the fracture of brittle inclusions are presented in detail. The model is a circular crack growing at constant speed from zero size until it attains a prescribed size. The far-field radiation pattern is the same as that of a simple combination of force doublets, and some qualitative similarities between force doublets and acoustic dipoles are noted. The initial shape of the far-field pulses due to the growing stage and the stopping is determined, but difficulties arise in accounting for the diffraction of a surface wave on the crack faces generated by the stopping of the crack.
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  • 15
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    Journal of nondestructive evaluation 1 (1980), S. 215-224 
    ISSN: 1573-4862
    Keywords: Acoustic emission ; slip ; microcracking ; deformations ; displacement field ; elastic waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The theory of elastic wave emission (i.e., acoustic emission; AE) from damage processes such as slip and microcracking is discussed. Analogous developments in the literature on earth-quake seismology and dynamic dislocation theory are noted and utilized. A general representation of the displacement field of an AE event is given in terms of the double-couple response to a distribution of “moment density tensor” in the source region. Results are specialized to a point source model and to a general far-field analysis of outgoing elastic waves, and conditions for validity of such representations and their low-frequency specializations are noted. Emitted wave fields are compared for tensile opening and slip events, and procedures which might enable the approximate determination of the size or area increase of tensile microcracks are discussed.
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  • 16
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    Journal of nondestructive evaluation 1 (1980), S. 157-181 
    ISSN: 1573-4862
    Keywords: EMAT ; radiation pattern ; transducer ; shear waves ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A Green's function calculation of the far-field radiation patterns of EMATs is presented. The approach is based on (a) closed form expressions for the eddy current and static magnetic field distributions, established by the EMATs, which react to produce the driving Lorentz forces, and (b) a Green's function derived from the steepest descent approximation to the far-field response of an arbitrary surface point force on a half space. Numerical results are presented, illustrating the radiation patterns of the three common EMAT designs. Included are vertically polarized shear waves as radiated by both meander coil and periodic magnet EMATs and horizontally polarized shear waves as radiated by the latter.
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  • 17
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    Journal of nondestructive evaluation 1 (1980), S. 123-136 
    ISSN: 1573-4862
    Keywords: fatigue life ; acoustic surface waves ; NDE ; ultrasonics ; cracks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract The present studies concentrated on predicting the remaining fatigue life for single fatigue cracks in the Paris regime of macrocrack propagation. Acoustic surface waves were used to interrogate the crack during cyclic fatigue. The inversion of the obtained scattering data provided crack depth and crack length as a function of the number of cycles applied in tension-tension fatigue. Auxiliary experiments were conducted to study the acoustic response of the crack to tensile and compressive loads, thought to open and close the crack. The technique may allow for new insights into the physics of the “crack closure” effect.
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  • 18
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    Journal of nondestructive evaluation 1 (1980), S. 201-206 
    ISSN: 1573-4862
    Keywords: fracture mechanics ; noncircular crack ; fatigue life ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A transfer function that converts an irregularly shaped two-dimensional crack into an equivalent circular crack of equal propagation lifetime is proposed. The methodology extends the exact elliptical to circular crack transfer function to other noncircular cracks with geometries that slightly deviate from the elliptical. Results for rectangular, symmetric dumbbell, and asymmetric dumbbell cracks are presented.
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  • 19
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    Journal of nondestructive evaluation 1 (1980), S. 249-261 
    ISSN: 1573-4862
    Keywords: Ultrasonics ; cracks ; surface roughness ; diffraction ; scattering ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Ultrasonic measurements from rough cracks were carried out using both broad-band and narrow-band methods. An analysis is suggested to determine parameters of the crack quantitatively such as size, shape, rms surface roughness, and distribution function of the surface roughness. Ultrasonic measurements of the parameters compare very well with the actual parameters of the defect.
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  • 20
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    Journal of nondestructive evaluation 1 (1980), S. 287-293 
    ISSN: 1573-4862
    Keywords: Photoacoustic microscopy ; SPAM ; silicon nitride ; surface crack ; turbine vanes ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Scanning photoacoustic microscopy (SPAM) was applied to silicon nitride turbine hardware for purposes of detecting fabrication defects. SPAM traces in selected areas of complex-shaped turbine stator vanes were obtained and indicate that surface-crack detection of the order of tens of microns is possible. Means were devised to allow for multiple scans in areas previously inaccessible to other nondestructive techniques capable of detecting defects in the 25- to 100-µm range. The results show that SPAM is applicable to reaction-bonded silicon nitride turbine components and capable of detecting small surface-related defects.
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  • 21
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    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 108-109 
    ISSN: 1618-2650
    Keywords: Best. von Ethosuximid, Valproat in Blutserum ; Chromatographie, Gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusion The proposed simultaneous determination of ethosuximide and valproate takes advantage of the similar properties of these substances that differ markedly from the other mainly used antiepileptic drugs. The volatility as well as the high blood concentration that are usual in therapeutics allow the measurement of ethosuximide and valproate directly in the extract without further concentration, e.g. by evaporation. On the other hand, one can optimise the methods for the determination of the other anticonvulsant drugs that are poorly volatile putting ethosuximide and valproate aside [1] and give up procedures using temperature programs with temperature differences of more than 100 ° C between the starting and the endpoint.
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  • 22
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    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 264-268 
    ISSN: 1618-2650
    Keywords: Best. von Wasser in Organ. Lösungsmitteln ; Chromatographie, Gas ; ECD, 8–170 ppm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Wasser ist in organischen Lösungsmitteln im ng-Bereich gas-chromatographisch ohne Derivatisierung mittels eines linearisierten Elektroneneinfangdetektors (ECD) nach Abtrennung auf einer Porapak QS-Säule bestimmbar. Ausreichend wasserfreie Lösungsmittel ließen sich durch Trocknen mit aktivierten 4 Å-Molekularsieben oder superaktiven Aluminiumoxiden W 200, Woelm Pharma, Eschwege, herstellen. Um Wasserblindwerte aus der Raumluft auszuschließen, ist es notwendig, sämtliche Operationen in einer Box mit Umlauftrocknung durchzuführen. Wassermengen bis zu 15 ng absolut sind bestimmbar. Im Konzentrationsbereich 7–150 μg/ml ist die Detektoranzeige für Wasser linear.
    Notes: Summary Water can be determined directly in organic solvents in the ng range after separation on a porapak-QS column using a linear electron-capture detector (ECD). Organic solvents can be dried by activated 4 Å molecular sieves to a water content of 5 μg/ml, about 0.3×10−3 molar. To exclude water contamination all operations, storage of solvents and standards included, were made in a glove box with permanent drying of the inside atmosphere. The EC-detector allows to determine 15 ng of water absolute. In the range of 7–150 μg/ml a linear response for water by the ECD has been found.
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  • 23
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    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 20-22 
    ISSN: 1618-2650
    Keywords: Analyse von Biolog. Substanzen, Steroidhormonen ; Chromatographie, Gas ; Anreicherungsverfahren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A new technique for the quantitation of very low concentrations of biological substances by gas-liquid chromatography is described. It is based on the direct concentration of the substances to be measured at the inlet of the chromatographic column. This is accomplished by injection of the substance into the chromatographic apparatus, whose column is kept at the condensation temperature of the sample. Repeated injection in separate portions results in accumulation of the substance. Chromatography is readily achieved by heating to the optimal temperature. This technique yielded promising results in the quantitation of several steroid hormones.
    Notes: Zusammenfassung Das Verfahren beruht auf der direkten Konzentrierung der zu bestimmenden Substanzen am Eingang der chromatographischen Säule. Sie erfolgt durch Injektion der Substanzlösung in die Säule bei einer Temperatur niedriger als der Schmelzpunkt, so daß die Substanz nicht eluiert werden kann. Eine wiederholte Injektion einzelner Portionen führt zur Anreicherung der Substanz, die dann nach Erhöhung der Säulentemperatur chromatographiert werden kann. Das Verfahren wurde mit guten Ergebnissen zur Bestimmung einiger Steroidhormone angewendet.
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    Fresenius' Zeitschrift für analytische Chemie 300 (1980), S. 387-402 
    ISSN: 1618-2650
    Keywords: Best. von Hexachlorbenzol, Polychlorcamphenen, Toxaphen, Kohlenwasserstoffen, chlorierte in Biolog. Material ; Chromatographie, Gas ; Umweltbelastung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary Fishes have been used to characterize pristine aquatic environments. In samples from a lake in the Tyrolian Alps (arctic char) and Northwest Ireland (pike), the Caspian Sea (sturgeon/Sevruga), the North Atlantic (salmon), the North Pacific (salmon) and the Antarctic Ocean at South Georgia (antarctic cod) hexachlorobenzene and polychlorinated camphene (PCC, Toxaphene) have been found. Samples are extracted by n-hexane/acetone (2+1), following a dimethylformamide/hexane clean-up of the lipid matrix. Adsorption chromatography on Florisil (1.25% water content) allows the elution of hexachlorobenzene, 4,4′-DDE and the polychlorobiphenyls (PCB) with n-hexane, while the mixture nhexane/diethyl ether (90+10) will elute the polychlorocamphenes (PCC) together with the hexachlorocyclohexane isomers and the DDT group. Identification of the PCC has been done by matching their retention indices measured by high resolution ECD glass capillary gas chromatography using the nalkyl-trichloroacetates as references and technical Toxaphene together with a slightly dehydrochlorinated product as authentic samples. The PCC content of the samples from the lakes in the European Alps and Northwest-Ireland, the North Pacific and the Antarctic Ocean was 125, 240, 285 and 68 ng of PCC per g of extractable lipids, respectively. The samples from the Caspian Sea and the North Atlantic had 1,625 and 3,500 ng of PCC per g of extractable lipids, respectively. All samples but the one from the Antarctic Ocean (liver) were spawn. Besides hexachlorobenzene and the PCC all samples contained polychlorobiphenyls (PCB), theα, β andγ-isomers of hexachlorocyclohexane, the compounds of the DDT-group and many other ECD-dectable not yet identified compounds.
    Notes: Zusammenfassung In Fischproben aus in erster Näherung unbelasteten Gebieten, dem Nordatlantik (Lachs), einem See in Nordwest-Irland (Hecht), einem Hochalpensee (Bergsaibling), dem Kaspischen Meer (Sternhausen), dem Nordpazifik (Lachs) und dem Antarktischen Ozean bei Südgeorgien (Antarktischer Dorsch) lassen sich Hexachlorbenzol und polychlorierte Camphene (PCC, Toxaphen®) nachweisen. Die Probe wird mit n-Hexan/Aceton (2+1) extrahiert. Die Lipide werden über eine Dimethylformamid/Hexan-Verteilung weitgehend abgetrennt. Adsorptions-Chromatographie an Florisil mit 1,25% Wassergehalt erlaubt die Elution von Hexachlorbenzol, 4,4′-DDE und der polychlorierten Biphenyle (PCB) mit n-Hexan; n-Hexan/Diethylether (90+10) eluiert die polychlorierten Camphene zusammen mit den Hexacyclohexan-Isomeren und der DDT-Gruppe. Die Identifizierung der PCC gelang über Vergleich der mit ECD-Capillar-Gas-Chromatographie unter Bezug auf die n-Alkyltrichloracetate gemessenen Retentionsindices. Als Standardsubstanz diente technisches Toxaphen, sowie ein durch methanolische KOH leicht dehydrochloriertes Produkt. Der PCC Gehalt lag bei den Proben aus dem Hochalpensee, einem See in Nordwest-Irland, dem Nordpazifik und dem Antarktischen Ozean bei 125, 240 bzw. 285 und 68 ng PCC/g extrahierbare Lipide. Die Proben aus dem Kaspischen Meer und dem Nordatlantik enthielten 1 625 bzw. 3 500 ng PCC/g extrahierbare Lipide. Bis auf die Probe aus der Antarktis (Leber) handelte es sich jeweils um Rogen. Neben dem Hexachlorbenzol und den Polychlorcamphenen wurden in allen Proben polychlorierte Biphenyle, dieα, β undγ-Isomeren des Hexachlorcyclohexans, die DDT-Gruppe und zahlreiche weitere bisher nicht identifizierte, mit dem ECD nachzuweisende Verbindungen gefunden.
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    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 20-31 
    ISSN: 1618-2650
    Keywords: Analyse von Polychlorbiphenylen, Aroclor, Clophen ; Chromatographie, Gas ; Glascapillaren, Electron capture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The composition of seven technical PCB-mixtures (Aroclor [Monsanto, USA] und Clophen A [Bayer, FRG]) has been investigated by high-resolution thin-film glass capillary gas chromatography with electron-capture detector. Methylpolysiloxane (SE 30) and purified Apiezon L have been used as liquid phases. Identification of the single PCB components has been performed by comparison of their retention indices with those of polychlorinated biphenyls defined by synthesis or with values calculated from retention index increments. For marking the individual PCB compounds a systematic numbering has been used.
    Notes: Zusammenfassung Die Zusammensetzung sieben technischer Gemische polychlorierter Biphenyle (PCB) mit unterschiedlichem Chlorierungsgrad (Aroclor- [Monsanto, USA] und Clophen A- [Bayer, Bundesrepublik Deutschland]-Typen) wurde mit hochauflösender Gas-Chromatographie mit Elektroneneinfang-Detektion in Dünnfilm-Glascapillaren mit Methylpolysiloxan (SE 30) und gereinigtem Apiezon L als flüssiger Phase untersucht. Die Identifizierung der Einzelkomponenten erfolgte durch chromatographischen Vergleich mit definierten Referenzsubstanzen oder Vergleich der aus Inkrementen berechneten Retentionsindices. Für die Kennzeichnung der Einzelkomponenten wird eine systematische Numerierung entsprechend der Substituentenbezifferung verwendet.
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    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 23-27 
    ISSN: 1618-2650
    Keywords: Best. von n-Butylzinnverbindungen in Luft ; Chromatographie, Gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung n-Butylzinnverbindungen (Tetra-, Tri-, Di-) wurden aus der angesaugten Luft an Chromosorb 102 adsorbiert, mit HCl-haltigem Diethylether desorbiert, falls nötig mit Methylmagnesiumchlorid umgesetzt und die methylierten Verbindungen gas-chromatographisch mit einem zinnspezifischen flammenphotometrischen Detektor bestimmt. Die mittlere Wiederfindungsrate (0,09–40 μg) von Bis(tri-n-butylzinn)oxid (TBTO) betrug: 93,3%; Streubereich der Einzelwerte ± 9,3% (P=95%, N=11). Wird 1 m3 Luft angesaugt, lassen sich noch Konzentrationen an n-Butylzinnverbindungen (Tetra-, Tri-, Di-) von 0,05 μg/m3 bestimmen. In einem mit einer TBTO-haltigen Dispersionsfarbe gestrichenen Raum wurde die Temperaturabhängigkeit der Tri-n-butylzinn-Konzentration in der Luft untersucht. Der Vergleich mit den Resultaten von Bestimmungen des Totalzinngehaltes läßt den Schluß zu, daß in der Luft nur Tri-n-butylzinnverbindungen vorlagen.
    Notes: Summary n-Butyltin compounds (tetra-, tri-, di-) have been adsorbed on Chromosorb 102 from the aspired air, desorbed with HCl-containing diethylether and, if necessary, converted to the corresponding methyl derivatives by reaction with methylmagnesium chloride. The derivatives were determined by GLC with a tin-specific flame photometric detector. The mean recovery (0.09–40 μg) of bis(tri-n-butyltin)oxide (TBTO) was 93.3%; tolerance limit ±9.3% (P=95%, N=11). With an air sample of 1 m3 it is possible to measure n-butyltin compounds (tetra-, tri-, di-) in concentrations down to 0.05 μg/m3. In a room coated with a TBTO-containing latex-based paint, the temperature dependence of the tri-n-butyltin concentration in the air has been studied. Comparison with results of total tin determinations allows the conclusion that the air contained only tri-n-butyltin compounds.
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    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 143-143 
    ISSN: 1618-2650
    Keywords: Best. von Phenolen ; Chromatographie, Gas ; neue Methylierungsreagentien
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 432-433 
    ISSN: 1618-2650
    Keywords: Analyse von Abwasser der Dimethylterephthalat-Produktion ; Chromatographie, Gas
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    Topics: Chemistry and Pharmacology
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    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 126-127 
    ISSN: 1618-2650
    Keywords: Analyse von Hydroxyfettsäuren ; Chromatographie, Gas ; ECD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 279-288 
    ISSN: 1618-2650
    Keywords: Analyse von Polysacchariden, Verdikkungsmitteln, Celluloseethern ; Chromatographie, Gas ; Zeisel-Spaltung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Im vorliegenden zweiten Teil der dreiteiligen Übersicht zur Analytik der Polysaccharide wird am Beispiel einer Methylhydroxyethylcellulose (MHEC) die Erfassung der Celluloseether und -mischether mittels der Gas-Chromatographie vorgestellt. Dabei handelt es sich um die Beschreibung einer quantitativen Methode hoher Empfindlichkeit, die erforderlich ist, um Cellulosederivate mit geringer Mischsubstitution zu identifizieren und zu unterscheiden. Dazu werden die Celluloseether in einer speziell entwickelten Apparatur mit Iodwasserstoffsäure bei 140°C erhitzt. Von den sich bildenden Spaltprodukten werden die abdestillierten Alkyliodide in gekühltem Hexylbromid aufgefangen, gas-chromatographisch getrennt und identifiziert; gebildete Olefine werden durch Bromaddition erfaßt. Reproduzierbarkeit: ≤3% rel. Erfassungsgrenze: = 0,01% Hydroxyethylcellulose (HEC). Die Methode eignet sich auch zur Erfassung von Estern, S-Alkylgruppen, Methylimidverbindungen, Glykolanteilen oder bestimmten Tensiden.
    Notes: Summary In this second part of the three-part review on analysis of polysaccharides the characterization of cellulose ethers and cellulose mixed ethers by means of gaschromatography is described. The identification of the wide varying field of this cellulose ethers is presented using methylhydroxyethylcellulose (MHEC) as an example. To differentiate all cellulose mixed ethers, even those with little substitution of one of the two ether components, the method has to work qualitatively and quantitativly with a high sensitivity. The cellulose ethers are treated with hydriodic acid at 140°C in a special apparatus. The alkyliodides formed are distilled into cooled hexyl bromide. They are separated and identified by gaschromatography. Olefins also formed are determined by addition of bromine. Reproducibility: ≤ 3% rel. Limit of detection: = 0.01 % Hydroxyethylcellulose (HEC). This method can also be used for the determination of esters, S-alkyl groups, methylimides, glycols and some detergents.
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    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 397-400 
    ISSN: 1618-2650
    Keywords: Best. von Benzo(a)-pyren in Erdölprodukten ; Chromatographie, Gas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A gas-liquid chromatographic method has been developed for the quantitive determination of benzo(a)-pyrene in petroleum products. At the 2 ppb benzo(a)pyrene level in a sample, the recovery is 87–90%. The detection limit is 50 ng. A column was employed with a liquid-crystal phase of bis(p-phenylbenzylidene)-bi-p-toluidine on Chromosorb.
    Notes: Zusammenfassung Das entwickelte gas-chromatographische Verfahren benutzt eine SÄule mit der Flüssig-Kristallphase von Bis(p-phenylbenzyliden)-bi-ptoluidin auf Chromosorb und gestattet im Bereich von 2 ppb Benzo(a)-pyren eine Wiederfindung von 87–90%. Die Nachweisgrenze liegt bei 50 ng.
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    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 32-32 
    ISSN: 1618-2650
    Keywords: Best. von Hexachlorcyclohexan, Hexachlorbenzol in Boden ; Chromatographie, Gas ; Extraktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 143-143 
    ISSN: 1618-2650
    Keywords: Best. von Hexachlorcyclohexan, Hexachlorbenzol im Wasser ; Chromatographie, Gas ; Extraktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 375-381 
    ISSN: 1618-2650
    Keywords: Best. von n-Alkanen, Pristan in Luft ; Chromatographie, Gas ; reine Luft
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary An analytical method was developed for measuring n-alkanes (C9 to C17) and other hydrocarbons in tropospheric air with mixing ratios of a few ppt (10−12) and higher. The hydrocarbons are collected in situ in absorption tubes, carefully protected against contamination and analysed later in the laboratory by gas chromatography. First data are reported for Atlantic air masses at the west coast of Ireland.
    Notes: Zusammenfassung Es wurde eine analytische Methode entwickelt zur Messung der n-Alkane (C9 bis C17) und anderer Kohlenwasserstoffe in reiner troposphärischer Luft mit Mischungsverhältnissen von einigen ppt (10−12) und aufwärts. Die Kohlenwasserstoffe wurden am Beobachtungsort angereichert, sorgfältig gegen Verunreinigung geschützt und später im Laboratorium gas-chromatographisch analysiert. Erste Daten für atlantische Luftmassen an der Westküste Irlands werden mitgeteilt.
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    Fresenius' Zeitschrift für analytische Chemie 302 (1980), S. 398-401 
    ISSN: 1618-2650
    Keywords: Best. von Wasserstoff in Magnesium ; Chromatographie, Gas ; Kapselmethode
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A new method, the capsule method, has been developed for analyzing hydrogen in magnesium with a standard deviation of about 4%. 1–2 g samples are made with a smooth surface and enclosed in a degassed iron capsule. The surface humidity is removed by a short annealing at 400°C, and the sample is subsequently degassed at 500–620°C in vacuum. The extracted hydrogen is measured by gas chromatography. The commercial magnesium analyzed contained from 0.2 to 8 ppm of hydrogen. The diffusion coefficient of hydrogen was measured to be: D=D 0e−Q/RT; where D 0=9.5 · 10−6 m2/s and Q=46,400 Joule/mole. The results obtained were interpreted as interstitial diffusion of hydrogen in magnesium.
    Notes: Zusammenfassung Zur Analyse von Wasserstoff in Magnesium wurde eine neue Methode, die Kapselmethode, entwickelt, 1–2 g schwere Proben werden mit einer glatten Oberfläche hergestellt und in eine gasfreie Kapsel eingeschlossen. Die Oberflächenfeuchtigkeit wird durch kurzes Anlassen bei 400°C entfernt und die Probe wird danach bei 500–620°C im Vakuum entgast. Der entfernte Wasserstoff wird mit einem Gas-Chromatographen gemessen. Die Standardabweichung beträgt etwa 4%. Das untersuchte technische Magnesium enthält zwischen 0,2 und 8 ppm Wasserstoff. Der gemessene Diffusionskoeffizient für Wasserstoff ist: D=D 0e−Q/RT; D 0=9.5 · 10−6 m2/s und Q= 46400 Joule/Mol. Die erhaltenen Resultate wurden als interstitielle Wasserstoffdiffusion im Magnesium interpretiert.
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    Fresenius' Zeitschrift für analytische Chemie 303 (1980), S. 389-393 
    ISSN: 1618-2650
    Keywords: Best. von Chrom(III), Chrom(VI) in Wasser ; Chromatographie, Gas ; Extraktion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The gas-chromatographic determination of Cr(III) and Cr(VI) in aqueous solution using di(trifluoroethyl)dithiocarbamate as an extracting agent (pH 3) is described. Best results were obtained with a column of OV-25 (3% on Chromosorb HPW, 100–120 mesh, 160–210
    Notes: Zusammenfassung Die Extraktion mit dem Reagens wird bei pH 3 durchgeführt. Als SÄulenmaterial hat sich am besten OV-25 (3% auf Chromosorb HPW, 100–120 mesh, 160–210
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    Fresenius' Zeitschrift für analytische Chemie 304 (1980), S. 337-349 
    ISSN: 1618-2650
    Keywords: Analyse von Biphenylen, polychlorierten in Umweltmaterial ; Chromatographie, Gas ; Glascapillar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The PCB-pattern of biological environmental samples of different trophic levels (fish, bird, man) and geographic areas (Alps, North Sea, North Atlantic) as seen by high-resolution glass capillary gas chromatography with electron capture detection is presented. The most evident variation of the pattern compared to a best fit simulation by technical mixtures is found for warm blooded species (eggs of birds and human milk). Only one trichloro-, but nine tetrachloro-biphenyls and 55 penta-to octachloro-biphenyls have been identified as PCB-components in biological samples. Compounds with 4,4′-disubstitution degrade very slowly, if at all (1,4-recalcitrance principle). Single component analysis of PCB in marine samples using glass capillary gas chromatography needs the preseparation from the ubiquitous polychloroterpenes (toxaphene, polychlorocamphene) and the DDT-group. Both complex mixtures can be separated successfully by adsorption chromatography on Florisil. Quantitation of PCB as a sum has been done by using recalcitrant diagnostic components and PCB-Clophen A 60 as the reference standard.
    Notes: Zusammenfassung Die Bestimmung der Einzelkomponenten der polychlorierten Biphenyle (PCB) in Umweltproben durch Glascapillar-Gas-Chromatographie auf Methylsilicon- oder Apiezon L-Phasen erfordert eine Vortrennung von den Polychlorterpenen (Toxaphen, Polychlorcamphen) und der DDT-Gruppe. Diese Trennung gelingt durch Adsorptions-Chromatographie auf Florisil. Die PCB-Muster im Fett des phytoplanktonfressenden Seefisches Menhaden (Brevoortia tyrannus) aus dem Nordatlantik, im Rogen der zooplanktonfressenden Salmoniden Seesaibling (Salvelinus alpinus) und Bachforelle (Salmo trutta m. fario) aus Bergseen in Tirol, und in der Leber der Süßwasserdorschart Quappe (Lota lota) aus dem Bodensee werden gezeigt. Die stärksten Veränderungen gegenüber einer aus technischen Gemischen hergestellten Simulationsmischung werden für Warmblütlerproben — Eier von Brandgans (Tadorna tadorna) und Küsten-Seeschwalbe (Sterna paradisea); Humanmilch — gefunden. Neben einem Trichlor- und neun Tetrachlorbiphenylen wurden 55 Pentabis Octachlorbiphenyle nachgewiesen. Komponenten mit einer 4 und/oder 3,5-Substitution in beiden Ringen werden beträchtlich langsamer abgebaut als anders strukturierte Komponenten (1,4-Rekalzitranz-Prinzip). Die Quantifizierung der PCB als Summe erfolgte über schwer abbaubare, signifikante Hauptkomponenten unter Verwendung eines Clophen A 60 PCB-Gemisches als Eichstandard.
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