LAUSR

The presence of the pyrethroids residues in different samples and the impact on human health is an increasing concern due to their widespread use. So, a method to determine eighteen pyrethroids in fish samples using a modified QuEChERS was developed. The clean-up procedure was performed by freezing samples overnight followed by dispersive solid phase extraction. The combination of C18, PSA and Z-Sep+ was optimized using a mixture design approach and samples were analysed using gas chromatography mass spectrometry. The method was validated using trahira samples and a scope extension was performed for tilapia and tainha. Recoveries were within 63-129%, relative standard deviation was ≤21.5% and the quantification limits were 5 µg kg-1 or 10 µg kg-1. The applicability of the method was assessed by analysis of fourteen real samples, in which residues were detected in four samples. Such detections demonstrate the importance of this sensitive method.