Analysis of water samples for trace levels of oxygenate and aromatic compounds using headspace solid‐phase microextraction and comprehensive two‐dimensional gas chromatography

Abstract

Headspace solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography (C2DGC) have been applied to the quantitative analysis of trace levels of oxygenate and aromatic compounds. The oxygenates studied were methyl-tert-butyl ether (MTBE) and ethyl butyl ether (EBE). The aromatics studied were the BTEX compounds, benzene, toluene, ethylbenzene, and xylenes. Both the oxygenates and aromatics are components of gasoline commonly found in groundwater near leaking underground storage tanks. The method involves extraction and preconcentration using a fused-silica fiber coated with a combination of polydimethylsiloxane and porous carbon followed by a volatility-by-polarity comprehensive two-dimensional gas chromatographic analysis with flame ionization detection. Experimental results yielded method detection limits of 360–630 parts per trillion (v/v), with calibration plots exhibiting a linear range over approximately three orders of magnitude. Reproducibility, as indicated by typical relative standard deviation (RSD) values for replicate runs, was 10%. C2DGC resolved all oxygenate and BTEX components from all traditional one-dimensional GC coeluters present in standard gasoline samples. The method is fast, is experimentally simple, and uses no solvent. © 1998 John Wiley & Sons, Inc. J Micro Sep 10: 597–604, 1998