title: Determination of dithiocarbamate pesticides in occupational hygiene sampling devices using the isooctane method and comparison with an automatic thermal desorption (ATD) method.
abstract: Two new methods for the determination of dithiocarbamate pesticides in occupational hygiene sampling devices are described. Dithiocarbamate spiked occupational hygiene sampling devices, consisting of glass fibre (GF/A) filters, cotton pads, cotton gloves and disposable overalls, were reduced under acidic conditions and the CS2 evolved as a decomposition product was extracted into isooctane. The isooctane was then analysed using gas chromatography with mass spectrometry, for CS2, which provided a quantitative result for dithiocarbamates. Recoveries obtained were generally within a 70-110% range and reproducibilities better than 15% RSD were typically achieved. The method has been successfully applied to samples collected during occupational exposure surveys. A second method employing automatic thermal desorption-gas chromatography-mass spectrometry (ATD-GC-MS) has also been developed and applied to the direct analysis of GF/A (airborne) samples. The method relies on the thermal degradation of dithiocarbamates to release CS2, which is used to quantify the analytes. Thiram spiked GF/A filters gave an average recovery of 107% with an RSD of 4%. The performance of the two analytical methods were directly compared by analysing sub-portions of GF/A filters collected during a survey to evaluate occupational exposures to thiram during seed treatment operations. Both methods performed well for the analysis of airborne (GF/A) samples and produced results in good agreement. ATD-GC-MS is the preferred method for studies involving GF/A (airborne) samples only. Because of the wider applicability of the isooctane method for other sampling devices, it is the preferred choice when carrying out surveys which require a dermal as well as respirable exposure assessment.
authors.affiliation: Health and Safety Laboratory, Broad Lane, Sheffield, S3 7HQ, UK. matthew.coldwell@hsl.gov.uk
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Coldwell
authors.forename: Ian
authors.initials: I
authors.lastname: Pengelly
authors.forename: Duncan A
authors.initials: DA
authors.lastname: Rimmer
mesh_terms: D002219:Carbamates; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D007306:Insecticides / Q000032:analysis*; D016273:Occupational Exposure; D016272:Occupational Health; D009795:Octanes / Q000737:chemistry*
chemical_list: D002219:Carbamates; D007306:Insecticides; D009795:Octanes; C045798:2,2,4-trimethylpentane