Analysis of pesticide residues in essential oils of citrus fruit by GC–MS and HPLC–MS after solid-phase extraction

A robust reliable method for the analysis of residues of pesticides in citrus groves was developed. Residues of twelve pesticides were extracted from citrus essential oils by SPE, separated by liquid chromatography and analyzed by GC–MS. In addition, ten pesticides were extracted by SPE, separated and analyzed by electrospray HPLC–MS. In the case of lemon essential oils, all twenty residues were separated by liquid/solid extraction on a mixed Florisil–C18 cartridge. The method enabled the analysis of the twenty pesticide residues at levels of 2 to 30 ppm with limits of detection ranging between 0.02 to 0.50 mg L−1.