Browsing by Subject "QuEChERS"

The literature review focused on the chemistry, uses, occurrence and toxicology of pesticide residues. Emphasis was placed on residue analytics and GC-MS/MS-methods. The aim of this study was to develop a reliable and reproducible GC-MS/MS-multi residue method for the determination of pesticide residues in poultry feed. First, two available sample preparation methods were compared. The methods chosen for comparison were QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) based on dispersive solid phase extraction (dSPE) and a liquid-liquid extraction method. In the former, the residues were extracted with water-acetonitrile mixture and the content of the dSPE tube containing MgSO4 was added to the extract to induce the liquid-liquid partitioning of the residues. The extract was then cleaned with primary and secondary amine (PSA) and octadecylsilane (C18) absorbents, filtered and analysed by GC-MS/MS. Based on the comparison, the QuEChERS method was chosen for the validation experiments. The QuEChERS method was proven to be a quick and simple method that provided better trueness than the other compared method. The repeatability was sufficient for 54 residue compounds. However, the recovery was between 70-120 % for 28 analytes and mainly less than 70 % for the remaining compounds. The limit of quantification was 0.01 mg/kg for 48 analytes. The developed multi residue method can be used for reliable and reproducible determination of 24 pesticide residues in poultry feed whereas the assessment of the method for the remaining compounds will be continued. After a more comprehensive evaluation, the method can be applied for other feed matrices in future multi residue studies.