Development of an analytical method based on QuEChERS and GC-ECD for the determination of deltamethrin residue in pine needles and pine nuts

Abstract In recent years, recurrent droughts have weakened the stone pine ( Pinus pinea) forests and favoured the emergence of harmful pests and diseases, including the Leptoglossus occidentalis. The stone pine’s nuts production has declined over the past five years. To control this hemipteran pest, a synthetic pyrethroid insecticide called deltamethrin is being tested. However, it is necessary to estimate the residue left by these treatments in forest stands. Therefore, a fast and robust analytical procedure was developed based on QuEChERS clean-up extraction, followed by gas chromatography coupled with an electron capture detector. This optimized method can detect residual concentrations of deltamethrin in pine needles and pine nuts up to a few µg kg − 1 . The results showed that two weeks after spraying, the deltamethrin content in the needles of stone pines decreased up to 75%, and after 9 months, its presence was like the nontreated trees.