摘要:

AbstractThe performance of cartridges with different polar and non‐polar stationary phases (C18, C8, C2, phenyl) has been investigated for the quantitative separation of butyltin and phenyltin species (TBT, DBT, MBT, MPT, DPT, TPT), and conditions have been established to optimize the separation, using gas chromatography with a flame photometric detector, to characterize the different organotin species. Optimum separation and preconcentration of organotins is based on retention in a C18cartridge and elution with 2 cm3of 1% (v/v) HBr and 0.1% tropolone solution in methanol, being successfully applied to seawater. Finally, the possibilities of the cartridges for selective elution and their use in direct non‐chromatographic speciation are discus

ISSN:0268-2605    

DOI:10.1002/aoc.590080703

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAn analytical procedure was developed for the determination of methylmercury in human hair using capillary gas chromatography with electron capture detection (GC–ECD). Hair samples are digested in alkaline solution/toluene in an ultrasonic bath at about 50°C. After cooling and treatment with hydrochloric acid (6 mol I−1) and a saturated solution of copper sulphate, the organic phase is extracted with a cysteine solution. Methylmercury is back‐extracted in toluene by adding copper sulphate and potassium bromide and analysed by GC–ECD using a DB17 capillary column. The practical detection limit of the method for methylmercury is 50 ng g−1using 100 mg of hair sample. Column performances and injection reproducibility have been evaluated. Results on 13 samples of human hair are presented and related to the total mercury concentration. The method, consisting of the optimization of similar analytical procedures through improvements in the various steps, allows for sensitive and reliable quantitation of methylmercury in hair with good precision an

ISSN:0268-2605    

DOI:10.1002/aoc.590080704

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA method is described for the determination of picogram amounts of inorganic mercury(II) and methylmercury(II) compounds in seawater. These compounds are first volatilized from the water samples by reduction to mercury (Hg0) and formation of methylmercury hydride (CH3HgH) by means of a sodium borohydride (NaBH4) solution and cryogenically focused onto a chromatographic stationary phase. Both mercury compounds are eluted according their boiling points and are passed through a pyrolysis tube, at 900°C, before entering the atomic flurescence detector. Absolute detection limits (3σ) are 1 and 2 pg for, respectively, inorganic mercury and methylmercury. For seawater analysis, detection limits of 0.1–1.0 ng I−1can be ach

ISSN:0268-2605    

DOI:10.1002/aoc.590080705

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractSeveral critical steps in the analytical procedure for organotin compounds in the environment are identified in this paper and solutions are suggested. In particular, an improved procedure for quenching excess Grignard reagent is described. After insight into the nature of losses was obtained, the use of internal standards made it possible to reduce further the method variability. The systematic optimization of the analytical procedure resulted in a well investigated and robust method for analysis of organotin compounds in zebra mussel samples. Organotin compounds (OTs) which enter the environment as a result of their use as biocides and their degradation products are regularly found in environmental samples. Many different analytical techniques are currently being used,1but little is known about their accuracy and precision.

ISSN:0268-2605    

DOI:10.1002/aoc.590080706

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractAnalysis of organotin compounds in environmental matrices is usually performed by chromatographic or spectroscopic techniques. Only a few papers dealing with organotin voltammetric determination have so far been published and this techniques does not seem very promising for organotin speciation. The reasons are likely to be found in the very low organotin concentration levels in the marine environment, in the complexity of environmental matrices and in the presence of several organotin compounds (butyl‐ and phenyltins), together with other metals, in samples; the latter leads to peak overlapping. In this paper we present a study of the influence of tropolone (2‐hydroxycyclohepta‐2,4,6‐trienone) on the voltammetric speciation of butyltin compounds. Results suggest that tropolone, being able to form complexes of different stability with tin and its compounds, improves the applicability of voltammetry to organotin determination by enhancing sensitivity and res

ISSN:0268-2605    

DOI:10.1002/aoc.590080707

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe determination of tributyltin (TBT) in sea food (mussel, oyster, fish) by a hydride generation–cold trapping–quartz furnace atomic absorption spectrometry procedure has been studied with emphasis on quality control. Large amounts of spiked materials have been prepared and stored either frozen, or frozen after freeze‐drying. Extraction of TBT by 0.1Mhydrochloric acid in methanolic solution is efficient (88–96%) for wet samples or freeze‐dried samples. It is also efficient with freshly spiked materials. Consumption of sodium borohydride by the matrix makes it necessary to use quite large amounts of reagent to obtain optimal sensitivity. Analysis of a fish‐tissue Certified Reference Material seems to indicate a partial debutylation of TBT during transport and/or storage of th

ISSN:0268-2605    

DOI:10.1002/aoc.590080708

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn order to investigate occupational exposure to various chemicals, blood samples from exposed subjects may be used. Such samples are usually collected locally for transport to an analytical laboratory. It is therefore essential that the necessary transport is performed under such conditions that an adequate stability of the analytes in the samples is maintained. The stability of trimethyl‐ and dimethyl‐lead species in blood at various storage temperatures, as well as the insulation capacity of different transport packages for blood samples, were determined. The results showed that alkyl‐lead compounds in spiked blood stored at room temperature were stable for 6 h and in a refrigerator for up to one week. Only in spiked blood stored at −20°C were the alkyl‐lead compounds found to be stable for more than one month. Blood samples from exposed subjects stored at −20°C were found to be stable for at least two months. One transport package used, found to maintain this temperature of prefrozen samples for up to two days, was a polystyrene transport box filled with crushed dry ice. This packing procedure is therefore recommended for transport of blood samples collected for evaluation of occupational exposure to alkyl

ISSN:0268-2605    

DOI:10.1002/aoc.590080709

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA procedure for trapping tetraalkyl‐lead (TAL) compounds in air is described. The system consists of a solid cartridge containing a mixture (65:35, w/w) in series of Porapak and Tenax. A contaminated atmosphere with a known concentration of TAL was generated in the laboratory. This atmosphere was trapped in the solid cartridge. After passing synthetic air through the system, the cartridge was extracted with hexane in an ultrasonic bath. The organic extract was concentrated under nitrogen current and the compounds were analyzed by GC–MS–SIM.Each step of the process was studied independently. Losses of volatile compounds in the evaporation step, the storage of the cartridge over 45 days before the extraction step and the break‐through volumes have been established in order to achieve optimization of the whole process. The analytical conditions of the final quantification include a linear range between 1.32 pg and 50.10 ng for Et4Pb, and 5.30 pg and 51.40 ng for Me4Pb. The detection limits are 0.66 pg, 3.40 pg, 1.07 pg, 1.05 pg and 2.60 pg for Et4Pb, Et3MePb, Et2Me2Pb, EtMe3Pb and Me4Pb, respe

ISSN:0268-2605    

DOI:10.1002/aoc.590080710

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe combination of a flow injection analysis system‐hydride generation (FIAS HG) and transversely heated graphite atomizer–atomic absorption spectrometry (THGA AAS) has been applied for the sensitive detection of organolead compounds [e.g. detection limit of trimethyl‐lead species (TriML): 32 ng l−1for a 0.5 ml sample loop] in the presence of inorganic lead. A mixture of hydrochloric acid and ethylenediaminetetra‐acetic acid (EDTA) as a carrier solution in the flow injection system suppressed interferences of inorganic lead. Calibration with various organolead compounds in the range 0.25–8 μg l−1was carried out in the presence of 10 mg l−1Pb2+without any interferences. Additionally, statistical aspects of the determination of trimethyl‐lead have been studied. Different parameters, e.g. working range, detection limit, recovery function etc., were calculated with respect to quality assurance i

ISSN:0268-2605    

DOI:10.1002/aoc.590080711

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractA rapid and sensitive method for the determination of trimethyl‐lead in water and road dust is described. It is based onin situethylation of ionic methyl‐lead by sodium tetraethylborate and the extraction of the compound formed into hexane. The extract is gas‐chromatographed and the lead species determined by microwave‐induced plasma atomic emission spectrometry (MIP‐AES). The reaction conditions are optimized and the method is applied to the analysis of artificial rainwater and road dust in the framework of an international round‐rob

ISSN:0268-2605    

DOI:10.1002/aoc.590080712

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY