INTER-LABORATORY STUDIES FOR THE VALIDATION OF SOLID-PHASE MICROEXTRACTION FOR THE QUANTITATIVE-ANALYSIS OF VOLATILE ORGANIC-COMPOUNDS IN AQUEOUS SAMPLES

Inter-laboratory studies were organised with the participation of twen ty laboratories for the purpose of validation of a new standard method using solid-phase microextraction (SPME) for the quantitative analysi s of volatile organic compounds (VOCs) in aqueous samples. The statist ical evaluation of the accuracy and precision of SPME was performed in accordance with the ISO standard concerning inter-laboratory studies on the basis of reference material and by comparison with the usual pu rge-and-trap and static headspace techniques. Comparable repeatability , reproducibility and accuracy were found with the SPME standard and t he reference methods. Better precision of SPME was obtained by extract ion from a small headspace over the aqueous phase than with the fibre immersed in water. The linearity was good in all cases and detection l imits were in the low ng/l range. Thus, it is concluded that SPME is a valid alternative technique for the analysis of VOCs at trace level i n various aqueous samples. (C) 1997 Elsevier Science B.V.