Fennel -seeds extract as an analyte protectant for the GC -MS/MS residue analysis of 182 pesticide in strawberries: Comparing the manual mixing and sandwich injection

The direct injection of acetonitrile sample extracts using GC-MS/MS is a challenging task in specific matrices of high polar components, like strawberries. In the current study, strawberry samples were extracted by acetonitrile and subsequently cleaned up using increased amounts of primary secondary amine and anhydrous magnesium sulfate. Furthermore, fennel-seeds extract using ethyl acetate was used as a natural analyte protectant during the GC-MS/MS analysis. This extract offers the required protection for the residue analysis of 182 pesticides in strawberries along all the run time of the GC-MS/MS. It was elucidated that, the sandwich injection does not perform an adequate mixing of the acetonitrile strawberry extract and the ethyl acetate fennel seed extract. Therefore, this mixing step was efficiently accomplished manually during the sample preparation. The developed technical enhancements resulted in the most consistent residue analysis method for many of the targeted pesticides during the routine analysis applications. The developed method was validated following EU validation guideline requirements "SANTE/11312/2021 " at 0.01 mg/kg and 0.05 mg/kg in strawberries. In addition, the developed method was applied to conduct a survey analysis of pesticide residue in strawberry samples in Qalyubia governorate, Egypt.