On-line solid-phase extraction coupled to supercritical fluid chromatography with diode array detection for the determination of pesticides in water

Supercritical fluid chromatography (SFC) with ten silica packed columns in series has been assayed for the multiresidue analysis of 184 pesticides in water samples. As the detection limits achieved by the electron-capture and diode array detectors were somehow high (0.1 mg/l), a solid-phase preconcentration coupled on-line with SFC was finally used to reduce these limits till 0.01 mu g/l. Before applying this solid-phase extraction-SFC system, a study of the variables that influenced the extraction step was made. After that, several small lough-water samples were analyzed identifying and evaluating 16 pesticides.