Multi-residue analysis method based on QuEChERS followed by ultra-high performance liquid chromatography coupled with diode-array detector for pesticides in human serum and breast milk.

Maternal fluids play a key role in the risk assessment regarding early life pesticide exposure as the chemicals can transfer to neonate through prenatal exposure and lactation. A developed UHPLC-DAD and modified QuChERS methods were validated for human serum and breast milk. Matrix effect of the biological samples were evaluated. Serum was extracted by unbuffered QuChERS method while breast milk was extracted by citrate buffered method with addition of hexane. Remaining lipid in breast milk extract was later removed using lipid-removal sorbent. Sample matrices caused huge impacted on low-sensitivity pesticides. The modified QuEChERS methods coupled with UHPLC-DAD were fully validated. Application in paired-serum and breast milk samples revealed 6 detected pesticides.