Simultaneous determination of six triazolic pesticide residues in apple and pear pulps by liquid chromatography with ultraviolet diode array detection

A method is described for the simultaneous determination of diclobutrazol, flusilazole, flutriafol, hexaconazole, paclobutrazol, and tetraconazole in apple and pear pulps used in baby food at a limit of 0.01 mg/kg. Apple and pear pulp samples are subjected to selective solid-phase microdispersion (S PMD) with SPE-ED Matrix-38 and acetone-cyclohexane, and the extracts are cl eaned up on a Florisil cartridge with hexane-cyclohexane-acetone. The extra cts are then analyzed by liquid chromatography with ultraviolet detection, using an octadecylsilane column with a gradient-programmed acetonitrile-wat er mobile phase. Recoveries were determined by spiking apple and pear pulps with the 6 pesticides under investigation at 0.1, 0.05, 0.03, and 0.01 mg/ kg. Six determinations were performed at each level for each pesticide. Rec overies were greater than or equal to 70% at the 0.01 mg/kg level.