Determination of glucuronide conjugates of hydroxyl triphenyl phosphate (OH-TPHP) metabolites in human urine and its use as a biomarker of TPHP exposure

•A method was developed for determination of para(p)- and meta(m)-OH TPHP glucuronides in urine.•Both p- and m-OH-TPHP glucuronides were detected in urine samples.•Concentration ranges of p- and m-OH-TPHP glucuronides were

In vitro studies using avian hepatocytes or human liver microsomes suggest that hydroxylation is an important pathway in the metabolism of triphenyl phosphate (TPHP), a chemical used as a flame retardant and plasticizer. TPHP metabolism can lead to the formation of para(p)- and meta(m)-hydroxyl-(OH-)TPHP products as well as their glucuronide conjugates. To determine whether the TPHP hydroxylation and depuration pathway also occurs in vivo in humans, the present study developed a sensitive method for quantification of p- and m-OH-TPHP glucuronides in human urine samples. In n = 1 pooled urine sample and n = 12 individual urine samples collected from four human volunteers from Ottawa (ON, Canada), p- and m-OH-TPHP glucuronides were detectable in 13 and 9 of the 13 analyzed samples and at concentrations ranging from

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