Determination of Pesticides and Transformation Products in Ginkgo biloba Nutraceutical Products by Chromatographic Techniques Coupled to Mass Spectrometry

Abstract

A QuEChERS (quick, easy, cheap, effective, rugged and safe) method combined with a clean-up step followed by gas chromatography-tandem mass spectrometry was validated for the determination of more than 150 pesticides in ginkgo biloba nutraceutical products. Due to the complexity of the matrix after QuEChERS extraction, the mixture of four sorbents (primary secondary amine, C18, Zr-Sep+ and graphitized black carbon) was used for the clean-up step. Matrix-matched standard solutions were utilized for calibration purposes. The method was validated and recoveries were evaluated at 10, 50 and 100 μg/kg, ranging between 73 and 107 %. The relative standard deviation for intra-day precision was always lower than 20 % and for inter-day precision lower than 25 %. Limits of detection ranged from 0.1 to 10.0 μg/kg; whereas, limits of quantification from 0.5 to 20.0 μg/kg. The validated method was successfully applied to the analysis of ginkgo nutraceutical samples. Nine samples were analysed and four samples contained pesticide residues (deltamethrin, kresoxym-methyl, myclobutanyl and procymidone). The highest concentration was found for deltamethrin, 10.1 μg/kg. Putative transformation products of pesticides, 3-phenoxybenzoic acid and BF 490-2 or BF 490-9, were also detected in the analysed samples using liquid chromatography-high resolution mass spectrometry analyaser (Exactive-Orbitrap).