Measurement of trihalomethanes and methyl tert-butyl ether in whole blood using gas chromatography with high-resolution mass spectrometry

The prevalence of disinfection by-products in drinking water supplies has raised concerns about possible adverse health effects from chronic exposure to these compounds. To support studies exploring the relation between exposure to trihalomethanes (THMs) and adverse health effects, an automated analytical method was developed using capillary gas chromatography (GC) and high-resolution mass spectrometry (MS) with selected ion mass detection and isotope-dilution techniques. This method quantified trace levels of THMs (including chloroform, bromodichloromethane, dibromochloromethane, and bromoform) and methyl tert-butyl ether (MTBE) in human blood. Analyte responses were adequate for measuring background levels after extraction of these volatile organic compounds with either purge-and-trap extraction or headspace solid-phase microextraction (SPME). The SPME method was chosen because of its ease of use and higher throughput. Detection limits for the SPME GC-MS method ranged from 0.3 to 2.4 ng/L, with linear ranges of three orders of magnitude. This method proved adequate for measuring the THMs and MTBE in most blood samples tested from a diverse U.S. reference population.