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

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, C-13(6)-phenyl ring). A synthetic method is presented for the preparation of the D-2-OPP internal standard. The C-13(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 C-12-/C-13(6)-/C-14-OPP. This method was developed to aid in assessments of human exposure to OPP during a variety of uses of the compound. Published by Elsevier Science B.V.