摘要:

AbstractA capillary electrophoretic method has been developed which achieves rapid quantitative separation and determination of ethylenediaminetetraacetic acid,N‐(2‐hydroxyethyl)ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminediacetic acid, and nitrilotriacetic acid in Hanford tank waste simulant (TWS). Direct UV detection of Cu2+/chelator complexes is used to achieve enhanced sensitivity. The qualitative and quantitative reliability of the method and the quality of separations, as given by efficiency and resolution, is presented. In addition, the limits of detection and linearity of detector response with concentration are given for each chelator. The selection of Cu as the UV‐absorbing species over other transition metals present in the waste is disc

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190402

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe elution order of the hop α‐ and β‐acids has been studied under different modes of electrokinetic separation. A model is advanced to explain the shorter migration times of the more hydrophobic β‐acids compared to the α‐acids in micellar electrokinetic chromatography (MEKC). For quality control of the bitter principles in hops, the ruggedness of electrokinetic separation could be improved by replacing MEKC by microemulsion electrokinetic chromatogra

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190403

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

年代:1996

数据来源: WILEY

摘要:

AbstractThermal treatment hyphenated with gas chromatography is a versatile and powerful tool in the study of polymer characterization. An inexpensive system where thermal treatment at different temperatures occurs inside a Programmable Temperature Vaporization injector (PTV) is described. The samples investigated, commercial plastics, are complex mixtures that contain several polymers and additives. These plastics as well as their pure constituents are subjected to multi‐step thermal treatment. The individual chromatograms of the various constituents of the polymeric sample are correlated with those of the final material in order to identify additives (thermal desorption) and degradation products (pyrolysis). Results obtained with the new method indicate the interesting potentials of the technique for the characterization of polymer compositions. Reproducibility of absolute and relative peak areas has been considered and found to be acceptable. The absence of a heated transfer line and switching valves, which are always present in conventional set‐ups, eliminates the risk of losses of high molecular weight components. Further advantages of the technique proposed are simplicity, versatility, and its inexpensive nat

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190404

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

年代:1996

数据来源: WILEY

摘要:

AbstractDetermination of carbamate residues in tobacco samples was carried out by three different methods, two having been described in the literature and one developed for the purpose of this work. The extracts were analyzed by HRGC‐FID (using derivatization), by HPLC‐RP with photodiode array detection and by Capillary Zone Electrophoresis (CZE) with UV detection. The extraction method developed used in conjunction with capillary zone electrophoresis showed to be the most suitable for carbamate residue analysis in real tobacco samples. The developed method presented better recovery results in relation to the others. CZE allowed the determination of carbamate residue in real tobacco sample while HPLC and HRGC could not do this, due to co‐elution pro

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190405

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

年代:1996

数据来源: WILEY

摘要:

AbstractA quick, simple and selective procedure has been developed for the determination of phenol,o‐cresol,m‐cresol, andp‐cresol in soil samples. The method is based on the gas chromatographic headspace analysis of phenols as acetate derivatives. These acetates were prepared directly in the wetted soil samples by acetic anhydride in the presence of KHCO3˙With this procedure sample handling is reduced to a minimum as desorption and derivatization of the analytes are developed from the wetted samples inside the vial of the head space sampler.The acetate esters were analyzed using a 60 m × 0.56 mm DIIDP capillary column (di‐isodecyl‐phthalate), using 2‐chlorophenol as an internal standard. The detection limit was between 0.03–0.08 μg g−1for the different species considered. Soil samples having carbon contents lower than 5 % can be analyzed by the

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190406

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe use of a simultaneous detection system for open‐tubular supercritical fluid chromatogrphic separation of aniline isomers, alkyl(C8to C18)dimethylamines, a dialkylmethylamine mixture, and an extract of a Japanese horseradish power “Wasabi” is demonstrated. A chemiluminescent nitrogen detector (CLND) and a flame ionization detector (FID) were configured at the end of the open tubular columnviaa zero‐ to dead‐volume tee. The dual detection was achieved with a post‐column split at a 1:2.5 ratio for the CLND and FID, respectively. The optimized CLND showed virtually no response to non‐nitrogenous components such as benzene, toluene, and methanol which were used as injection solvents in these

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190407

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

年代:1996

数据来源: WILEY

摘要:

AbstractThere is a need for rapid, on‐line, gas chromatographic analysis of trace levels of hydrogen sulfide and carbon oxysulfide in the oil‐from‐coal industry. In order to improve an existing method based on a polymer bed concentrator, a porous layer open tubular column, and a flame photometric detector, time‐optimization of the various steps involved was attempted. Use of a redesigned concentrator, changed column operating conditions, and a photoionization detector reduced analysis times from 6.5 to 3 min and cycle times from 8 to 3 min. This could be achieved without compromising the 10 ppb detection limit r

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190408

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

年代:1996

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190411

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

年代:1996

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190412

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

年代:1996

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240190413

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

年代:1996

数据来源: WILEY