ISSN:0935-6304    

DOI:10.1002/jhrc.1240180102

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe aim of this study was to develop a technique for performing automatic static headspace analysis of volatiles without a cryogenic device. Reconcentration of solutes was accomplished using a graphitized carbon coated precolumn between two splitting points and stopping carrier gas flow during injection. Chromatographic profiles of volatile compounds from ground coffee compared with split and splitless injections provide confirmation of the good sensitivity of the technique. The analysis of a standard mixture covering a wide range of volatility confirms that the described technique might be useful to achieve enrichement of low volatile headspace compounds, even if discrimination against the various components is present.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180103

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

年代:1995

数据来源: WILEY

摘要:

AbstractA single 0.2 m focal length near‐IR monochromator providing a 0.8–3.2 nm effective bandpass was evaluated as spectrometer for F‐, Cl‐, Br‐, I‐, S‐, and P‐selective atomic emission detection in capillary gas chromatography. With optimized plasma conditions and careful wavelength selection, interferences from eluting hydrocarbons were almost eliminated for all the elements studied (element‐to‐carbon selectivities between 1000:1 and 10000:1). For Cl and S, other heteroatoms were found not to cause cross‐interferences. F‐, Br‐, I‐, and P‐selective detection, however, was complicated by this second type of non‐specificity. For these atoms, elemental confirmation was carried out by analyzing the samples also for heteroatoms po

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180104

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

年代:1995

数据来源: WILEY

摘要:

AbstractTrace atmospheric gases have been sampled using potassium‐iodide‐based reactant traps for ozone removal. GC‐MS analysis revealed the presence of organic iodine compounds which were present neither in the atmosphere nor as contaminants of the materials used, but more likely arose from reactions of organic gases or aerosols sampled with reactive iodine or hypoiodite released from reaction of ozone with potassium iodide in the traps. Losses of the individual organic trace gases measured were not, however, observed as a result of this mechanism. Several cautions in identifying unknown compounds from the atmosphere when using potassium iodide ozone traps are disc

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180105

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

年代:1995

数据来源: WILEY

摘要:

AbstractTemperature programmable injectors with liner diameters ranging from 1 to 3.5 mm are evaluated and compared for solvent split injection of large volumes in capillary gas chromatography. The liner dimensions determine whether a large sample volume can be introduced rapidly or has to be introduced in a speed controlled manner. The effect of the injection technique used on the recovery ofn‐alkanes is evaluated. Furthermore the influence of the liner diameter on the occurrence of thermal degradation during splitless transfer to the analytical column is studied. Guidelines are given for the selection of the PTV liner internal diameter best suited for specific application

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180106

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

年代:1995

数据来源: WILEY

摘要:

AbstractAn isotope ratio mass spectrometer and an ion trap mass spectrometer have been coupled in parallel to one gas chromatograph. Using this arrangement both the13C/12C ratio and the mass spectrum of a given compound can be measured simultaneously under identical gas chromatographic conditions. Although column connection fittings are employed to split the capillary eluate, chromatographic performance was barely impaired. Development of the system has been monitored by recording δ13C values of the constituents of Grob test mixture no. 2. The accuracy and reliability of system performance has also been tested

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180107

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

年代:1995

数据来源: WILEY

摘要:

AbstractSupercritical fluid chromatography with inductively coupled plasma‐mass spectrometric detection is a new and useful technique for the analysis of organometallic compounds. An interface has been developed for coupling these techniques. The interface is compact, easy to assembel, and causes minimal disruption to either instrument. A series of organotin, organoarsenic, and organorion compounds has been used to evaluate the interface and ICPMS as a detector for SFC. The effect of analyte concentration and restrictor temperature on peak intensity has been investigated and the effect of the mobile phase on the plasma has also been studied to assess background interference from changes in the plasm

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180108

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe on‐line coupling of a liquid‐liquid extraction system with capillary gas chromatography using atomic emission detection (GC‐AED) has been studied. The required large volumes of about 100 μl of an iso‐octane solution can be introduced into the GC‐AED system by using the AED solvent vent and a solvent vapor exit in front of the capillary analytical column. Test solutions containing several pesticides were detected using the carbon, chlorine, nitrogen and sulfur channels. Analyte detectability (in concentration units) was improved significantly and low concentractions of the test compounds could be determined (1–5 ng/ml). Aqueous samples were on‐line extracted and analyzed. The precision of the large‐volume injection itself as well as the total extraction‐GC‐AED system was satisfactory (RSD ofca.2 and 4%, respectively). As a real‐life application, several ground water

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180109

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe coupling of column liquid chromatography on‐line with mass spectrometry using post‐column phosphate suppression is described. A membrane suppressor is used to remove the non‐volatile phosphate ions from the mobile phase after the chromatographic separation prior to introduction into the mass spectrometer. Using post‐column phosphate suppression by a membrane device phosphate concentrations up to 10 mM phosphate, at a mobile phase flow rate of 0.1 ml/min, could be removed for more than 99% without any decay of the sensitivity of the MS detection.Using a new antidepressant tetracyclic basic compound, ORG 4428, and some structure related compounds as model compounds electron impact as well as chemical ionisation spectra of all compounds could be obtained. The set‐up could be used for several weeks running, using a phosphate containing mobile phase, without any loss of pe

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180110

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe direct enantioselective analysis of 3‐, 4‐, and 5‐hydroxy fatty acids from biological material has been achieved by enantioselective multidimensional gas chromatography (enantio‐MDGC) with heptakis(2,3‐di‐O‐methyl‐6‐O‐tert‐butyldimethylsilyl)‐ or (2,3‐di‐O‐acetyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin as chiral stationary phase. All the bacteria investigated produced polyesters of ena

ISSN:0935-6304    

DOI:10.1002/jhrc.1240180111

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

年代:1995

数据来源: WILEY