GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC IDENTIFICATION AND QUANTITATION OF URINARY PHENOLS AFTER DERIVATIZATION WITH 4-CARBETHOXYHEXAFLUOROBUTYRYL CHLORIDE, A NOVEL DERIVATIVE

Urinary phenol is analyzed widely to determine benzene exposure in hum ans. Most methods utilize direct measurements of phenols after extract ion from urine using gas chromatography or high-performance liquid chr omatography, We describe a novel derivatization of urinary phenols usi ng 4-carbethoxyhexafluorobutyryl chloride after extraction from urine and subsequent analysis by gas chromatography-mass spectrometry. The d erivative elutes at significantly higher temperature than phenol and t he method is free from interferences from more volatile components in urine. We also observed excellent chromatographic properties of these derivatives. In addition, we observed strong molecular ions for the 4- carbethoxyhexafluoro butyryl derivative of phenol (m/z 344), p-cresol (m/z 358) and the internal standard 3,4-dimethylphenol (m/z 372) and o ther characteristic ions in the electron ionization, thus aiding in un ambiguous identification of these compounds. The protonated molecular ions (m/z 373 for derivatized phenol, m/z 359 for derivatized p-cresol and m/z 373 for the internal standard) were the base peaks (relative abundance 100%) in the chemical ionization, although other secondary p eaks were less abundant. The assay is linear for phenol concentration of 1-100 mg/l. The within-run and between-run precisions were 4.8% ((X ) over bar=52.4, S.D.=2.5 mg/l) and 8.1% ((X) over bar=53.0, S.D.=4.3 mg/l) respectively, and the detection limit was 0.5 mg/l.