title: Determination of methyl 5-hydroxy-2-benzimidazole carbamate in urine by high-performance liquid chromatography with electrochemical detection.
abstract: A high-performance liquid chromatographic (HPLC) assay for methyl 5-hydroxy-2-benzimidazole carbamate (5-HBC) in urine was developed in order to assess the exposure of workers to the pesticide carbendazim. 5-HBC is measured in urine after hydrolysis, sample clean-up through a strong cation-exchange (SCX) column and extraction with ethyl acetate. HPLC with electrochemical detection provides selective and sensitive determination of 5-HBC with a detection limit of 5 micrograms/l. A C18 reversed-phase column was used with 0.06 M ammonium acetate solution (pH 8)-methanol (73:27) as mobile phase. The method was validated with respect to hydrolysis of urine samples, analytical recovery of spiked 5-HBC, stability of 5-HBC conjugates, limit of detection, background and precision. The overall analytical recovery from urine was better than 60%. 5-HBC, excreted in urine as a conjugate, was stable for at least one year when stored at -20 degrees C. A background of ca. 5 micrograms/l was detected in urine from some non-occupationally exposed persons. Between-day coefficients of variation as calculated from the results of the stability test were 7, 4 and 4% for concentrations of 61, 244 and 295 micrograms/l 5-HBC, respectively (n = 16).
authors.affiliation: Department of Occupational Toxicology, TNO Medical Biological Laboratory, Rijswijk, Netherlands.
authors.forename: L H
authors.initials: LH
authors.lastname: Leenheers
authors.forename: R
authors.initials: R
authors.lastname: Engel
authors.forename: W E
authors.initials: WE
authors.lastname: Spruit
authors.forename: W J
authors.initials: WJ
authors.lastname: Meuling
authors.forename: M J
authors.initials: MJ
authors.lastname: Jongen
mesh_terms: D001562:Benzimidazoles / Q000633:toxicity / Q000652:urine*; D002138:Calibration; D002219:Carbamates / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002852:Chromatography, Ion Exchange; D004563:Electrochemistry; D005659:Fungicides, Industrial / Q000633:toxicity / Q000652:urine*; D006801:Humans; D016273:Occupational Exposure
chemical_list: D001562:Benzimidazoles; D002219:Carbamates; D005659:Fungicides, Industrial; C080388:methyl 5-hydroxy-2-benzimidazole carbamate; C006698:carbendazim