ISSN:0935-6304    

DOI:10.1002/jhrc.1240140202

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

年代:1991

数据来源: WILEY

摘要:

AbstractA Curie‐point headspace sampler (CPHS) equipped with a purge and trap sampler has been developed for use with capillary gas chromatography. The new system can handle a variety of samples, including gases, liquids, and solids, and can also be used as a pyrolyze

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140203

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

年代:1991

数据来源: WILEY

摘要:

AbstractAn automated system employing a purge and trap technique with capillary gas chromatography and electron‐capture detection (ECD) has been developed for the analysis of trace levels of volatile halogenated hydrocarbons and applied to the determination of the compounds in environmental samples such as rainwater and ambient air. The operation of the method, its application to environmental samples, and the results obtained are described. Use of the system ensured good chromatographic resolution and high accuracy, even with trace levels of the compound

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140204

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

年代:1991

数据来源: WILEY

摘要:

AbstractA simple and effective solid phase extraction (SPE) method using silica gel micro glass columns has been developed for the separation of diesel fuel into groups of aliphatic, and mono‐, di‐ and polyaromatic hydrocarbons. It is based on a stepwise gradient of dichloromethane inn‐pentane. The resulting fractions were analyzed by capillary gas chromatography with a flame ionization detector and coupled gas chromatography‐mass spectrometry.Commercially available standards, and retention indices and mass spectra were used for identification of individual aromatic compounds. The principal polycyclic aromatic hydrocarbons (PAHs) in diesel fuel are naphthalene, biphenyl, fluorene, phen‐anthrene and their alkylated derivatives. Sulfur‐containing PAHs are mainly represented by methyl‐substituted diben

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140205

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe use of a porous glassy carbon (PGC) material as a packed‐column SFC stationary phase has been previously demonstrated [1]. The material is further characterized in terms of its retention characteristics. The effects of variations in mobile phase composition, pressure, and temperature conditions are evaluated. Variation of temperature and pressure yielded expected results, specifically, decreased solute capacity factors with increased mobile phase density. The choice of supercritical fluid mobile phase allows the most notable control of solute retention; this was evaluated by adding low percentages of organic modifiers of varying molecular weights to the supercritical carbon dioxide mobile phase. PGC‐SFC provides reversed phase characteristics similar to those found for PGC‐HPLC. Porous glassy carbon has selectivity characteristics previously unavailable in supercritical fluid chromatography. Use of porous glassy carbon in supercritical fluid chromatography may provide distinct advantages in difficult analytical separations, allowing separations of molecules with only slight structural differ

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140206

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

年代:1991

数据来源: WILEY

摘要:

AbstractA hybrid mass spectrometer with an EBQQ configuration was used to investigate two approaches to trace dioxin analysis: high resolution gas chromatography – high resolution mass spectrometry (HRGC‐HRMS) and high resolution gas chromatography – mass spectrometry – mass spectrometry (HRGC‐MS‐MS). It is shown that selected ion monitoring (SIM) HRGC‐HRMS exhibits better selectivity for dioxins separated on a cyanopropyl column than is otherwise obtained under medium resolution mass spectrometry (3,000 resolution), while optimization of conditions for HRGC‐MS‐MS allowed the observation of 350 femtograms of the highly toxic 2,3,7,8‐TCDF at a S/N ratio of 5:1. Both methods were applied to environmental sample

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140207

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis report describes the selective detection of volatile nickel, vanadium, and iron metalloporphyrins in crude oil samples. An atomic emission detector (AED) was used for simultaneous detection of these metals using the Ni 301.2 nm, V 292.4 nm, and Fe 302.1 nm emission lines. Detection limits for these metals range from 0.05 to 5 pg/sec. The presence of volatile forms of these metals in several crude oil samples has been confirmed.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140208

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

年代:1991

数据来源: WILEY

摘要:

AbstractPreparative‐grade bonded β‐ and γ‐cyclodextrin stationary phases were used as the packing material of liquid chromato‐graphic analytical microcolumns. Although the resulting columns are characterized by relatively low efficiency, the high selectivity of the cyclodextrin phases nevertheless allows their successful use for the separation of different classes of isomeric compounds that are difficult to resolve on conventional LC stationary phases. Examples of baseline (or almost baseline) separations of a number of isomeric compounds, including isomeric polycyclic aromatic hydrocarbons, are presented to demonstrate the analytical potential of such columns. Retention behavior of the separated isomers is discussed based on the structure of the solute molecule and the possibility of its inclusion into the molecular cavity of cyclodextrin stationa

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140209

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

年代:1991

数据来源: WILEY

摘要:

AbstractCapillary columns of 0.3–0.35 mm internal diameter and 0.3–7.7 m length, packed with 3 to 30 μm octadecylsilica stationary phases as used for liquid chromatography, were applied to gas chromatographic separation of low boiling hydrocarbons.Van Deemterplots for these columns showed the optimum column efficiency to occur at linear velocities of 4–5 cm/s. A short column was applied to the rapid separation of components of a natural gas and impurities in standard gases, while a long column was applied to the separation of complex mi

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140210

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

年代:1991

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240140211

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

年代:1991

数据来源: WILEY