Application of QuEChERS based method for the determination of pesticides in nutraceutical products (Camellia sinensis) by liquid chromatography coupled to triple quadrupole tandem mass spectrometry.

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) based method has been evaluated and validated for the determination and quantification of approximately 100 LC-amenable pesticides in nutraceutical products obtained from green tea (Camellia sinensis). Extraction was performed with acidified acetonitrile (acetic acid 1% (v/v)), and additional clean-up steps were not necessary. Pesticides determination was achieved using ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). Total running time was 11 min. Pesticides were quantified using matrix-matched calibration. Recoveries ranged from 70% to 117% and relative standard deviation (RSD) was lower than 20% at concentration levels of 25, 50 and 100 μg/kg for intra-day precision and equal or lower than 25% for inter-day precision. Limits of quantification (LOQ) were equal or lower than 25 μg/kg. The validated method was applied to commercial nutraceutical products, detecting acetamiprid (56 μg/kg) and carbendazim (13 μg/kg) in two samples.