ANALYSIS OF VOLATILE ORGANIC-COMPOUNDS IN WATER AND SOIL SAMPLES BY PURGE AND MEMBRANE MASS-SPECTROMETRY

A new method, purge-and-membrane mass spectrometry (PAM MS), is introd uced for the analysis of volatile organic compounds (VOCs) in water an d soil samples, In this method, VOCs are purged from water or soil sam ples with an inert gas and the stream is directed through a sheet memb rane module. The VOCs pervaporate through the membrane directly into t he ion source of a mass spectrometer. The limits of detection for nonp olar VOCs such as halogenated hydrocarbons, benzene, toluene, and xyle nes were below micrograms per liter in water samples and at low microg rams per kilogram levels in soil samples. The correlation coefficients measured for the compounds studied were typically better than 0.9999 and 0.9975 in water and soil samples, respectively. The relative stand ard deviations were between 0.5 and 2.0% with water samples and betwee n 4.8 and 14.0% with soil samples. These results demonstrate excellent linearity and repeatability. PAM MS thus provides a highly sensitive, selective, accurate, solvent-free, and rapid analytical method. Tens of samples can be analyzed reliably within 1 h.