Simultaneous determination of trace levels of nine haloacetic acids in biological samples as their pentafluorobenzyl derivatives by gas chromatography/tandem mass spectrometry in electron capture negative ion chemical ionization mode.

Abstract

Haloacetic acids (HAAs) are environmentally and medically important chemicals. No analytical method is currently available to analyze EPA-regulated HAAs in biological samples at environmentally relevant low concentrations. Clinical studies of this class of chemicals are also limited by the lack of analytical techniques of high sensitivity and precision. We now report a new analytical method using gas chromatography/ion trap mass spectrometry for quantifying nine HAAs present inplasma, urine, and water at picogram per milliliter levels. The derivatization reactions of HAAs with pentafluorobenzyl bromide were optimized and detection with an electron capture negative ion chemical ionization mode was employed to enhance the sensitivity. Selected ion monitoring and selected reaction monitoring methods were utilized for quantitation. The detection limits of HAAs in plasma, urine, and water were 25-1000 pg/mL. Accuracies varied from 86.6 to 118.1% (intraday) and 81.7 to 119.6% (interday). Precisions (CV) varied from 0.9 to 19.9% (intraday) and 0.8 to 19.8% (interday), and linearities (r2) varied from 0.9732 to 0.9998 (intraday) and 0.9422 to 0.9987 (interday), respectively. Methyl tertbutyl ether and diethyl ether provided the highest extraction recoveries for the HAAs (74.9-107.2%). The method was applied successfully to a kinetic investigation of low levels of HAAs in humans consuming chlorinated drinking water.