title: Determination of organophosphate diesters in urine samples by a high-sensitivity method based on ultra high pressure liquid chromatography-triple quadrupole-mass spectrometry.
abstract: Organophosphate (OP) diesters in urine samples have potential use as biomarkers of organism exposure to environmentally relevant OP triester precursors and in particular OP triester flame retardants. This present study developed a quantitatively sensitive ultra high pressure liquid chromatography (UHPLC-MS) based method for urine and the determination of OP diesters (i.e. diphenyl phosphate (DPHP), bis(2-chloroethyl) phosphate (BCEP), bis(2-chloroisopropyl) phosphate (BDCIPP), di-n-butyl phosphate (DNBP), di(2-ethylhexyl) phosphate (DEHP), bis(1-chloro-2-propyl) phosphate (BCIPP), and bis(2-butoxyethyl) phosphate (BBOEP)). Fortified with the 7 OP diesters, 1mL of human urine sample was cleaned up using weak anion exchange solid phase extraction and eluted with high ionic strength ammonium acetate buffer. Subsequently, 4 non-chlorinated OP diesters were directly determined using UHPLC-electrospray(-)-triple quadrupole-MS (UHPLC-ESI(-)-QqQ-MS), and UHPLC-ESI(+)-QqQ-MS was used for determination of 3 chlorinated OP diesters after methylation using diazomethane. Recovery efficiencies of OP diesters ranged from 88 to 160% at three spiking levels (0.4, 2 and 10ng/mL urine). Matrix effects (MEs) and method limits of quantification (MLOQs) were 15-134% and 0.10-0.32ng/mL urine, respectively. Concentrations of OP diesters in n=12 urine samples (from 4 Canadian residents, 2014) varied as follows, nd-<0.28 (DNBP), nd-1.29 (DPHP), nd-<0.28 (DEHP), <0.16-12.33 (BCEP), nd-1.17 (BCDIPP) and nd-0.68ng/mL (BCIPP).
authors.affiliation: Department of Chemistry, Carleton University, Ottawa, ON, Canada K1S 5B6. Electronic address: guanyong.su85@gmail.com.
authors.forename: Guanyong
authors.initials: G
authors.lastname: Su
authors.affiliation: Department of Chemistry, Carleton University, Ottawa, ON, Canada K1S 5B6. Electronic address: robert.letcher@canada.ca.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse & School of the Environment, Nanjing University, Nanjing, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Yu
mesh_terms: D002021:Buffers; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004952:Esters; D005411:Flame Retardants / Q000032:analysis; D006801:Humans; D010755:Organophosphates / Q000652:urine*; D009994:Osmolar Concentration; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D002021:Buffers; D004952:Esters; D005411:Flame Retardants; D010755:Organophosphates
keywords: Canadian residents; Organophosphate diesters; Organophosphate flame retardants; UHPLC–ESI–QqQ–MS; Urine