Determination of thiophanate-methyl and its metabolites at trace level in spiked natural water using the supported liquid membrane extraction and themicroporous membrane liquid-liquid extraction techniques combined on-line with high-performance liquid chromatography

On-line supported liquid membrane (SLM) extraction and microporous membrane liquid-liquid extraction (MMLLE) techniques for sample preparation of natu ral water samples have been developed for the determination of thiophanate- methyl (TM), carbendazim (MBC) and 2-aminobenzimidazole (2-AB) using revers ed-phase HPLC. The combination of SLM extraction and MMLLE offers extractio n conditions that makes it possible to determine a wide variety of compound s, i.e., permanently charged. ionisable and non-polar at sub ppb level. The detection limits obtained after extraction are about 0.1 mu g/l for MBC an d 2-AB using SLM, and 0.5 mu g/l for TM using MMLLE and the precision is be tter than 5% for both systems. Typical enrichment rates are 0.6 and 2.7 tim es/min using SLM and MMLLE, respectively. (C) 2000 Elsevier Science B.V. Al l rights reserved.