Eleven phenols and 2,4-dichlorophenoxyacetic acid, compounds that may be found in body fluids of humans exposed to pesticides, are derivatized with pentafluorobenzyl bromide and characterized by gas chromatography with electron capture detection. These derivatives are further characterized by positive and negative chemical ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and gas chromatography-Fourier transform infrared spectroscopy. Negative chemical ionization mass spectra of all derivatives have an anionic base peak derived from the parent analyte. In the positive mode the nonchlorinated derivatives have base peaks indicative of the analyte, while chlorinated derivatives are cleaved to give the pentafluorobenzyl cation as base peak. The possibility is explored that ortho-substituted phenols might be formed as byproducts in these derivatizations.

We have developed a method for determining selected chlorinated phenols and phenoxy herbicides in urine. The process of preparing the samples includes acid hydrolysis, extraction with benzene, derivatization with diazoethane, and column chromatography cleanup. We quantify the more volatile compounds by using capillary column gas chromatography/positive chemical ionization/mass spectrometry/mass spectrometry. Less volatile compounds are quantified by using electron capture negative chemical ionization in a single stage mass spectrometry mode. Quality control samples are included in each analytical run, and the results demonstrate that the analytical system is in control. Positive values for the target analytes are determined on the basis of appropriate relative retention time, a signal-to-noise ratio greater than 3:1, and a calculated concentration greater than 1 ppb. We determine the chlorine isotope ratios for each compound to assess the presence or absence of interferences. This analytical method has been applied in a case-control study of 199 individuals to examine exposure to the 12 target analytes.