Determination of ortho-phenylphenol in human urine by gas chromatography–mass spectrometry

Abstract

A sensitive gas chromatographic–mass spectrometric method was developed to quantitate total o-phenylphenol (OPP) (free plus conjugates) in human urine. Conjugates of OPP were acid-hydrolyzed to free OPP, derivatized to the pentafluorobenzoyl ester derivative and analyzed via negative-ion chemical ionization gas chromatography–mass spectrometry. Two stable isotope analogs of OPP were shown to be suitable as internal standards for this method (D 2-phenol ring, 13 C 6 -phenyl ring). A synthetic method is presented for the preparation of the D 2-OPP internal standard. The 13 C 6 -OPP analog was also shown to be useful as an alternate test material for laboratory-based exposure studies. The limit of quantitation for this method was 1 ng OPP/ml urine. Calibration curves were linear for the analyte over the concentration range of 0.5–1117 ng OPP/ml urine. Relative recovery of OPP from urine ranged from 97.0 to 104.7%. Low levels of OPP (mean=6±7 ng/ml; n=22) were found in control human urine samples. The method was validated with urine samples obtained from human volunteers undergoing a dermal exposure study with 12 C -/ 13 C 6 -/ 14 C -OPP. This method was developed to aid in assessments of human exposure to OPP during a variety of uses of the compound.