ONLINE 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 column s in series has been assayed for the multiresidue analysis of 184 pest icides in water samples. As the detection limits achieved by the elect ron-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-p hase extraction-SFC system, a study of the variables that influenced t he extraction step was made. After that, several small lough-water sam ples were analyzed identifying and evaluating 16 pesticides.