Application of solid-phase disk extraction followed by gas and liquid chromatography for the simultaneous determination of the fungicides: captan, captafol, carbendazim, chlorothalonil, ethirimol, folpet, metalaxyl and vinclozolin in environmental waters

Abstract

Extraction disks (C 18 Empore) were used for the isolation and trace enrichment of several fungicides: captan, captafol, carbendazim, chlorothalonil, ethirimol, folpet, metalaxyl and vinclozolin from drinking, river and estuarine water. From most of the pesticides the recoveries (determined by liquid chromatography with diode array detection (LC-DAD) at 210 nm) varied from 68 to 116% with a coefficient of variation (C.V.) of 3–7%. The recoveries observed for carbendazim and ethirimol in natural waters using LC-DAD were 14 and 30%, respectively. These apparent low recoveries were attributed to the measurement (matrix interferences) and values of 40 and 120%, respectively, were achieve when using liquid chromatography thermospray mass spectrometry (LCTSP-MS) selected ion monitoring (SIM) and positive ion (PI) mode detection. Analytical determinations were also carried out using gas chromatography with electron capture detection (GC-ECD) for the direct analysis of five fungicides, with the exception of carbendazim, ethirimol and metalaxyl. Confirmation of the identity of the fungicides was carried out by gas chromatography-mass spectrometry (GC-MS) in the electron impact mode and LC-TSP-MS using both positive and negative ion modes and filament-on. The limits of detection at S/ N = 3 were 5, 10, 100 and 500–2000 ng/1 when GC-ECD, GC-MS, LC-DAD and LC-TSP-MS were used, respectively.