title: Biological monitoring of the five major metabolites of di-(2-ethylhexyl)phthalate (DEHP) in human urine using column-switching liquid chromatography-tandem mass spectrometry.
abstract: We present a fast and reliable on-line clean-up HPLC-method for the simultaneous determination of the five major urinary metabolites of di-(2-ethylhexyl)phthalate (DEHP) namely mono-(2-ethyl-5-carboxypentyl)phthalate (5carboxy-MEPP), mono-[2-(carboxymethyl)hexyl]phthalate (2carboxy-MMHP), mono-(2-ethyl-5-hydroxyhexyl)phthalate (5OH-MEHP), mono-(2-ethyl-5-oxohexyl)phthalate (5oxo-MEHP) and mono-(2-ethylhexyl)phthalate (MEHP). These metabolites represent about 70% of an oral DEHP dose. We for the first time succeeded to reliably quantify 5carboxy-MEPP and to identify 2carboxy-MMHP as major metabolites in native urines of the general population. The analytical procedure consists of an enzymatic hydrolysis, on-line extraction of the analytes from urinary matrix by a restricted access material column (RAM), back-flush transfer onto the analytical column (betasil phenylhexyl), detection by ESI-tandem mass spectrometry and quantification by isotope dilution (limit of detection (LOD) 0.25 microg/l). Median concentrations of a small collective taken from the general population (n=19) were 85.5 microg/l (5carboxy-MEPP), 47.5 microg/l (5OH-MEHP), 39.7 microg/l (5oxo-MEHP), 9.8 microg/l (MEHP) and about 37 microg/l (2carboxy-MMHP). The presented method can provide insights into the actual internal burden of the general population and certain risk groups. It will help to further explore the human metabolism of DEHP-an occupational and environmental toxicant of great concern.
authors.affiliation: Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Schillerstrasse 25, D-91054 Erlangen, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Preuss
authors.forename: Holger M
authors.initials: HM
authors.lastname: Koch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Angerer
mesh_terms: D000328:Adult; D002648:Child; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004051:Diethylhexyl Phthalate / Q000378:metabolism* / Q000633:toxicity / Q000652:urine*; D004784:Environmental Monitoring / Q000379:methods; D006801:Humans; D010795:Phthalic Acids / Q000652:urine*; D010968:Plasticizers / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D010795:Phthalic Acids; D010968:Plasticizers; D004051:Diethylhexyl Phthalate