A Streamlined Approach Utilizing Herbal Extracts as a Natural Analyte-Protectant for the Pesticide Residues Analyses in Strawberry Using Gc-Ms/Ms

In multi-class pesticide residue analyses, QuChERS is the commonly used extraction method. Nevertheless, the direct injection of acetonitrile extracts to GC-MS/MS is a challenging task. This was mainly appeared in particular matrices of high contents of polar components with minor non-polar co-extracted ones. The current study aims to introduce a modified QuChERS protocol employing the two-layer direct injection approach for the acetonitrile extracts into GC-MS/MS. Ethyl acetate extract of fennel was employed as a natural analyte protectant. A comparative study revealed that conventional QuChERS protocol suffers from irreproducible results along with deteriorated peak characteristics, particularly when samples analysis batch exceeds 8 samples. Therefore, samples were extracted by acetonitrile and subsequently cleaned up by double the amounts of PSA. Two-layer injection using a natural herbal extract, fennel extract, was applied to protect the tested pesticides especially late eluted. This has ameliorated the peak characteristics in conjunction with maximum reproducibility attained over the analysis batch of 20 samples. In which more than 85% of the studied 182 pesticides were successfully achieved acceptable performance. The developed protocol was validated in accordance with EU validation guideline requirements “SANTE 2019” at 0.01 mg/Kg and 0.05 mg/Kg in strawberries. The validated protocol was successfully applied to 37 strawberry samples, collected from the Egyptian local market.