ISSN:0935-6304    

DOI:10.1002/jhrc.1240111002

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe useful combination of capillary supercritical fluid chromatography with ultraviolet multichannel detection is demonstrated by the analysis of selected pesticides and herbicides. In this application the advantages of compound identification by ultraviolet spectrometry are appended to the separating capability of capillary supercritical fluid chromatography. A pseudo oncolumn detection approach is used. Compromises from the theoretically ideal conditions for both capillary SFC and the multichannel UV detector are made to achieve a practical interfacing of the chromatographic and spectrophotometric techniques. Detection limits are at the low nanogram levels.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111003

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe development of an on‐line SFC‐FTIR method with supercritical carbon dioxide as mobile phase requires information about the nature of the FTIR spectrum of a solute dissolved in supercritical or liquid CO2. The wavenumber of maximum absorbance of the carbonyl stretching vibration was quantitatively studied versus temperature and CO2density. FTIR spectra recorded in supercritical or liquid CO2have been compared to their vapor‐phase and condensed‐phase spectra for various

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111004

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

年代:1988

数据来源: WILEY

摘要:

AbstractConcurrent solvent evaporation with a loop‐type interface was used for on‐line HPLC‐CGC in the analysis of methylated dibenzothiophene (DBT) isomers in oil samples. The chromatographic behavior of 20 methyl DBT's was studied by HPLC on an aminopropylsilane DBTA phase and by GC on a selective methyl‐phenylsilicone phase. That provided a method for analyzing by GC‐flame photometric detection, the individual components of the DBT family, previously picked out of the crude oil matrix by HPLC. The GC oven temperature was shown to be critical during HPLC eluent introduction into the GC pre‐column. Too high a temperature induced a severe broadening of early eluted peaks whereas a temperature too close to the boiling point of the liquid at the inlet pressure induced double peaks. Optimized conditions were retained on this basis and may be used for the analysis of other families of polyaromatic h

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111005

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe cause of an observed acceleration in the free release static coating process of a capillary when more polar solvents are added to alkanes as stationary phase solvents has been studied. By using a computer program, 9 of the relevant physical parameers were calculated in relation to the composition of the solvent hixtures. Curves of these parametersvscomposition of the mixures were drawn. From the results it can be deduced that the change of these parameters with the increase of polar solvents in the solution, is probably insufficient to explain the drastic increase of the free release static coating speed. A physical model is proposed to calculate the depth of the meniscus around which sufficient heat can be transferred into the evaporating surface per unit time, to evaporate the solvent at a rate that the coating speed indicates. It is demonstrated that when pentane‐acetone mixtures are used to coat a capillary, the depth of the meniscus indeed is greater than when pure pentane is used. The proposed model may lead to a better understanding of phenomena involved in the static coating proces

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111006

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

年代:1988

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111007

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

年代:1988

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111008

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

年代:1988

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111009

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

年代:1988

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111010

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

年代:1988

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240111011

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

年代:1988

数据来源: WILEY