Determination of thiophanate-methyl and its metabolites at trace level in spiked natural water using the supported liquid membrane extraction and the microporous 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 natural water samples have been developed for the determination of thiophanate-methyl (TM), carbendazim (MBC) and 2-aminobenzimidazole (2-AB) using reversed-phase HPLC. The combination of SLM extraction and MMLLE offers extraction conditions that makes it possible to determine a wide variety of compounds, i.e., permanently charged, ionisable and non-polar at sub ppb level. The detection limits obtained after extraction are about 0.1 microg/l for MBC and 2-AB using SLM, and 0.5 x Lg/l for TM using MMLLE and the precision is better than 5% for both systems. Typical enrichment rates are 0.6 and 2.7 times/min using SLM and MMLLE, respectively.