COMPARISON OF DIFFERENT METHODS FOR THE DETERMINATION OF VOLATILE ORGANIC-COMPOUNDS IN WATER SAMPLES

The aim of this work was to compare the characteristics of three metho ds, membrane inlet mass spectrometry (MIMS), purge-and-trap gas chroma tography-mass spectrometry (P&T) and static headspace gas chromatograp hy (HSGC), for the determination of volatile organic compounds in wate r samples as used in routine analysis. The characteristics examined in cluded linear dynamic ranges, detection limits of selected environment ally hazardous volatile organic compounds (e.g. toluene, benzene and t richloroethene) in water, required analysis time and reproducibility o f the analytical methods. The MIMS and P&T methods had the lowest dete ction limits for all the tested compounds, ranging from 0.1 to 5 mu g l(-1). Linear dynamic ranges using the MIMS method were about four ord ers of magnitude and using the P&T method about two orders of magnitud e. Detection limits of the HSGC method were 10-100 times higher than t hose of the other two methods, but the linear dynamic ranges were larg er, even up to six orders of magnitude. The analysis time per sample w as shortest for the MIMS method, from 5 to 10 min, and ranged around f rom 35 to 45 min for the HSGC and P&T methods, The reproducibilities o f the methods were of the same order of magnitude, in the range of 1-1 3%. Agreement between the analytical results obtained for spiked sampl es and for environmental water samples by the three different methods was very good. (C) 1997 Elsevier Science B.V.