摘要:

AbstractThe peculiarities of the flow splitting technique for sample injection into a capillary column have been discussed. A comparative investigation of reproducibility of the analytical results obtained for two gas chromatographic systems using flow splitting [1) sample injector‐packed predolumn‐splitter‐open tubular capillary column and (2) sample injector‐splitter‐open tubular capillary column] has been carried out. It was experimentally shown that the first system ensures considerably better reproducibility for the results concerning the composition of the analyzed mixtures. Other advantages of the first system are also

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractGas chromatographic profiles have been generated from different batches of a polypropylene/polyethylene copolymer. The profiles generated from polymer pellets have been obtained by dynamic headspace/capillary gas chromatography analysis. Initially 10 to 40 peaks were chosen at random from the quantitative reports and transferred to a data table. After appropriate scaling the table has been analyzed by a multivariate statistic program, SIMCA (Soft Independent Modeling of Class Analogy) a pattern recognition technique. The method has been used to differentiate batches according to sensory qualities of the final packaging product and changes in polymer peilet production.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe atmospheric levels of C1‐ and C2‐halocarbons are determined by trapping on an adsorbent, thermodesorption, cryofocussing, gas chromatographic separation on a thick‐film capillary, and electron‐capture detection. The various aspects relevant to reliability and accuracy are discussed, such as type of adsorbent, range of detector response, and levels of contaminants present in blanks. These in turn have implications for optimum sample size and amount of adsorbent. The adopted method is suitable for routine analysis of airborne halocarbons at variable locations. The air concentrations of C1‐ and C2‐halocarbons on the ground of mountain forests are similar to those in cities, a fact which supports the hypothesis that chlorocarbons are involved in the initiation of a phytotoxicological phenomenon commonly referred to as “fo

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110114

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA system to analyze a complex mixture simultaneously on two different columns after one single on‐column injection is described. The splitting device, the possibilities of component identification by searching in a data base for Kovats indices on two different polarity stationary phases, and a practical example of an essential oil analysis are presente

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110115

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA frit restrictor interface for capillary column supercritical fluid chromatography/mass spectrometry (SFC/MS) has been constructed and used for the analysis of high boiling point alkanes. Packed column SFC/MS is described using both a moving belt liquid chromatographic/mass spectrometric interface and a thermospray source in the filament‐on mod

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110116

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe theoretical and practical implications of simultaneous temperature/pressure and synchronized density/temperature programming are considered. Examples are shown for separations of dimethylpolysiloxanes where these techniques provide superior separation over their analogous isothermal programming methods.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110117

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractFor clinical and environmental analyses utilizing capillary gas chromatography/mass spectrometry (GC/MS), increased sensitivity and speed of analysis are highly desirable. These performance advantages are realized using a WCOT column of 100 μm i.d. as compared to the more conventional 200 μm i.d. capillary columns. The improved sensitivity of capillary direct GC/MS with the 100 μm i.d. column for the confirmation of drugs of abuse will be demonstrated. For environmental analysis, the superior efficiency and resolution of the 100 μm i.d. column can be employed for the separation of priority pollutants. This approach is more amenable to capillary direct GC/MS providing a more effective interface to the mass spectrometer. As a result improved sensitivity and a considerable decrease in analysis time is achieved over that obtained with the larger diameter environmental specialty phase colu

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110118

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractNarrow bore columns (100 μm) have successfully been applied in the analysis of commercial lemon oils. On these columns, high resolution is obtained in a short analysis time. Different Brazillian lemon oils are characterized qualitatively and quantitatively

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110119

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA radio frequency plasma detector for element specific detection in gas chromatography is described. The detector is comprised of a radio frequency (300 kHz) discharge between electrodes in helium, and utilizes a low‐resolution emission spectrometer to monitor selected spectral emission lines produced when the helium discharge decomposes and excites the atomic constituents in the chromatographic column effluent. The spectrometer is tuned to an atomic emission line in the near‐infrared portion of the spectrum, and the emission intensity from the discharge region of a selected line is used to monitor the concentration of the element producing that line. Acceptable detector sensitivity was achieved by the use of a high‐throughput optical system. Selectivity was achieved by a combination of correct line selection, plasma and carrier gas purification, and plasma gas d

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110120

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA direct sample injection technique was developed for supercritical fluid chromatography in a packed capillary column, with carbon dioxide as mobile phase and a flame ionization detector. The method allowed solutions, neat liquids, and even solids to be introduced as samples. Also, extraction with supercritical carbon dioxide was combined with this method to separate polymer additives.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240110121

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY