摘要:

AbstractSolid‐phase microextraction (SPME) has been applied to the quantitative analysis of 60 volatile organic compounds (VOCs) in drinking water. Equilibration curves for the partitioning of the VOCs between the fiber coating and fortified water obtained at 20, 50, and 80 °C are found between the theoretical curves for completely agitated and non‐agitated samples. Two important factors for the amount adsorbed by the SPME fiber coating are the extraction time and the fiber coating/water distribution coefficient,KFW. Both depend on the sample temperature, but in a counteracting manner: Increasing the temperature shortened the equilibration times, especially for the heavier VOCs, but also lead to lowerKFWvalues, and consequently a lower sensitivity of the method.KFWvalues are determined for 33 of the VOCs at 40, 60, and 80°C and the heats of adsorption,–ΔH, are calculated. The nature of the adsorption is found to be exothermic which explains the decreasing sensitivity of the method with increasing temperature. Detection limits were typically from 20 ng/l to 200 ng/l, except for the very light VOCs with which detection difficulties were encountered. For all of the VOCs the linear range extended from the lowest concentration at which they were actually detected to at least 5 mg/l. The precision, 3% average standard deviation when an internal standard was used, was satisfactory for most quantitative routine analysis. SPME was also applied to head‐space (HS) analysis of drinking water through the coupled equilibrium between water/head‐space/fiber coating. HS‐SPME is demonstrated to have shorter equilibration times than SPME directly from the water and equal sensitivities, except for the very light VOCs. Water samples from a drinking water plant contaminated in the low μg/l range with 1,1,1‐trichloroethane, trichloroethene and tetrachloroethene were analyzed. There seems to be a reasonable agreement between results obtained by SPME and purge&trap. It is concluded that SPME has a great potential for drinki

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181002

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe current method of choice for the extraction of flammable or combustible liquid resides from fire debris samples is passive headspace concentration using activated charcoal strips (ACS) for adsorption of the liquid residues followed by elution with carbon disulfide or other suitable solvent. Presently, we report a new technique based on headspace solid‐phase microextraction which has been successfully applied to the identification of a wide range of accelerants commonly seen in arson analysis. The SPME technique developed is simple, inexpensive, rapid, and eliminates the use of the highly flammable and toxic solvent carbon disulfide. Results using this SPME method have been directly compared to results obtained via the ACS technique for light, medium, and heavy petroleum distillates as well as gasoline. All of the accelerants studied were accurately identified by the SPME method with equal or greater sensitivity compared to the ACS metho

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181003

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

年代:1995

数据来源: WILEY

摘要:

AbstractA chiral stationary phase prepared by bondingL‐valine‐t‐butylamide to XE‐60 has been coated on glass and metal capillaries. The performances of the chiral glass and metal columns were equivalent to those of commercial fused silica capillary columns. The thermal stability of the glass column was examined up to 280°C. It was found that no appreciable change in separation factor (α value) was observed up to 230°C. The α values gradually decreased between 240 and 260°C, and enantiomer separation was no longer achieved at 280°C. It was concluded that the allowable upper limit temperature of the chiral stationary phase is between 230 and 240°C in the isothermal mode, andca260°C in temperature

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181004

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

年代:1995

数据来源: WILEY

摘要:

AbstractAdsorptive enrichment on hydrophobic adsorbents, thermal desorption, and capillary gas‐chromatographic analysis have been used to determine volatile organic compounds in extremely humid stack‐gas emissions from the residential burning of brown‐coal briquets. One hundred and fifty two compounds were identified and quantified. Quantitative emission factors were determined for the identified individual compounds in relation to the amount of the fuel used. These factors enable a first assessment of the pollution of the city of Leipzig with volatile organic compounds resulting from the burning of indigenous li

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181005

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

年代:1995

数据来源: WILEY

摘要:

AbstractPerdeuterated α‐1,2,3,4,5,6‐hexachlorocyclohexane (α‐PDHCH) was synthesized and isolated in pure form. α‐PDHCH was baseline separated from unlabeled α‐HCH by high resolution gas chromatography on different stationary phases. α‐PDHCH was also resolved into its enantiomeric forms by application of a chiral GC phase. Furthermore, chiral chromatography of a mixture of labeled α‐PDHDH and unlabeled α‐HCH resulted in four peaks. Standard solutions of α‐PDHCH are recommended both as recovery standard for sample clean‐up and as internal standard for the quantitation of chlorinated hydrocarbons with GC/MS or GC/E

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181006

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

年代:1995

数据来源: WILEY

摘要:

AbstractAfter the restrictions on production and use of PCBs, Ugilec 141, a technical mixture of dichlorobenzyldichlorotoluenes (DBDTs), has been used as a PCB substitute in hydraulic systems. In the Netherlands, the production, import and use of Ugilec 141 has been forbidden since 1988. A method has been developed for the analysis of Ugilec 141 in waste mineral oils to control waste oil import and processing.The method development was based on modification of procedures for the analysis of PCBs in oil and dioxins in fatty matrices and analysis was performed with gas chromatography with mass spectrometry. For sample clean‐up, several combinations of column chromatography with activated carbon, alumina, and silica gel have been tested to obtain extracts free from matrix interferences. An internal standard of13C‐labeled DBDT was examined to check recoveries from the clean‐up procedures. Quantification was performed by comparison with the six most abundant peaks of an external Ugilec 141 standard mixture. Validation experiments showed a linear range from 0.25 to 60 mg Ugilec 141 kg−1oil, a reproducibility of 3% and a limit of determination of 0.25 mg Ugilec 141 kg−1waste oil.The method was applied in a survey of 70 samples of waste mineral oils from producers all over the Netherlands; this revealed levels below the limit of determination and one positive sample with a concentration of 5.7±0.1 mg Ugilec 141 kg−1oil. In an inspection inquiry, one contaminated oil was found containing 116 ± 9 g Ugile

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181007

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

年代:1995

数据来源: WILEY

摘要:

AbstractA gas chromatographic (GC)‐mass spectrometric (GC‐MS) method has been developed for the routine analysis of 11 fragrance substances in cosmetics: cinnamic alcohol, cinnamic aldehyde, eugenol, hydroxy citronellal, α‐amyl cinnamic aldehyde, geraniol, isoeugenol, coumarin, dihydrocoumarin, citronellal and citral. Methods for sample preparation of various types of cosmetic products, prior to GC analysis, have also been developed and proved to be rugged. Detection limits of all of target fragrance substances were approximately 1 ppm. Calibration curves of the target fragrance substances analyzed by GC were found to be linear in the investigated concentration range, 0.005% – 0.50%. The recoveries of the target fragrances from various types of cosmetic products were 80% – 116% and the relative standard deviations of the quantitative analysis of the target fragrance substances were

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181008

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

年代:1995

数据来源: WILEY

摘要:

AbstractThe capillary electrophoretic (CE) separation of the enantiomers of three binaphthyl compounds is investigated. Several CE modes such as cyclodextrin (CD) modified capillary zone electrophoresis (CZE) (CD‐CZE), micellar electrokinetic chromatography (MEKC), cyclodextrin electrokinetic chromatography (CD‐EKC),etc.are employed for the simultaneous enantiomer separation of the three solutes. The successful separation was achieved by combining two modes, in other words by using more than two chiral selectors. A development of the CE enantiomer separation is demonstrated for the binaphthyl compounds. The enantioselectivity of binaphthyl compounds is alo briefly discus

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181009

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

年代:1995

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181010

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

年代:1995

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240181011

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

年代:1995

数据来源: WILEY