Combination of solid-phase extraction and dispersive liquid-liquid microextraction for detection of cypermethrin and permethrin in environmental water

A new solid-phase extraction and dispersive liquid-liquid microextraction (SPE-DLLME) method coupled with gas chromatography electron capture detection (GC-ECD) was established for the detection of cypermethrin and permethrin in river water. The samples were firstly extracted using a large-volume SPE procedure and the eluents of SPE were further purified and enriched by the following DLLME. Good linearity was observed in the range of 0.015-3.87 mu g L-1 for cypermethrin and 0.065-16.2 mu g L-1 for permethrin with the correlation coefficient (r) >= 0.9995. The limits of detection based on S/N = 3 were 0.48 and 3.81 ng L-1 for cypermethrin and permethrin, respectively. Under optimized conditions, the enrichment factors for cypermethrin and permethrin were 1545- and 2138-fold, respectively. The developed method was successfully used to detect the two pyrethroid residues in river water samples.