title: Analysis of ethylenethiourea as a biomarker in human urine using liquid chromatography/triple quadrupole mass spectrometry.
abstract: Ethylenebisdithiocarbamates (EBDCs) are widely used fungicides. Ethylenethiourea (ETU), the main metabolite and also a contaminant in the commercially available products, is of major toxicological concern. In this study, a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) is described for the analysis of ETU in human urine after a single-step extractive derivatization using pentafluorobenzyl bromide (PFBBr). Analysis was carried out using selected reaction monitoring (SRM) in the positive ion mode. Quantification of ETU was performed using [(2)H(4)]-labeled ETU as internal standard (IS). The limit of detection (LOD) was determined to 0.05 ng/mL. The method was linear in the range 0.1-54 ng/mL urine and had a within-run precision of 3-5%. The between-run precision was determined at an average urine level of 2 and 10 ng/mL urine and found to be 9%. The inter-batch precision was 6%. To validate ETU as a biomarker of exposure, the method was applied in a human experimental oral exposure to the commercial fungicide Ridomil Gold, containing 64% mancozeb and 4.5% ETU. Two healthy volunteers received 8.9 microg/kg body weight (b.w.) Ridomil Gold in a single oral dose followed by urine sampling for 104 h post-exposure. The elimination half-life of ETU was estimated to 17-23 h.
authors.affiliation: Department of Occupational and Environmental Medicine, Institute of Laboratory Medicine, University Hospital, SE-221 85 Lund, Sweden. christian.lindh@med.lu.se
authors.forename: Christian H
authors.initials: CH
authors.lastname: Lindh
authors.forename: Margareta
authors.initials: M
authors.lastname: Littorin
authors.forename: Gunvor
authors.initials: G
authors.lastname: Johannesson
authors.forename: Bo A G
authors.initials: BA
authors.lastname: Jönsson
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000409:Alanine / Q000031:analogs & derivatives / Q000493:pharmacokinetics / Q000652:urine; D015415:Biomarkers / Q000737:chemistry / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D005031:Ethylenethiourea / Q000032:analysis* / Q000737:chemistry; D005260:Female; D005659:Fungicides, Industrial / Q000493:pharmacokinetics / Q000652:urine; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D015415:Biomarkers; D005659:Fungicides, Industrial; C028175:metalaxyl; D005031:Ethylenethiourea; D000409:Alanine