Speaker
Description
Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that resist environmental degradation. Due to their semi-volatility and lipophilicity, they are easily transported through air, water, soil, and food, and tend to bioaccumulate in living organisms. Long-term exposure to these compounds can cause various acute and chronic health effects, emphasizing the importance of monitoring their presence in biological matrices such as blood, urine, and milk.
Milk is a complex biological matrix rich in lipids, proteins, and carbohydrates, providing a suitable medium for the accumulation of lipophilic contaminants and serving as a valuable indicator of human exposure to these pollutants.
The aim of this study was to optimize a procedure for the extraction and analysis of 24 pesticides, including OCPs and PCBs, in human milk using gas chromatography coupled with an electron-capture detector (GC-ECD). Cow’s milk was used for method optimization due to its availability and compositional similarity to human milk.
The optimization followed a “step-by-step” approach, including the evaluation of extraction mixtures (acetone/hexane at different ratios), protein denaturation agents (acetic acid and sodium acetate), purification steps (Florisil, alumina, and QuEChERS), and lipid removal using sulfuric acid added at different extraction stages. The acceptance criterion for method performance was recovery between 80% and 120%.
The optimized method, based on liquid–liquid extraction with hexane/acetone (50:50 v/v), cleanup with concentrated sulfuric acid and alumina column, and concentration using a Kuderna–Danish apparatus, ensures reliable recovery and quantification of target analytes and can support future national monitoring of human exposure to OCPs and PCBs through breast milk analysis.
Keywords: OCPs, PCBs, optimization, human milk, GC-ECD, step-by-step.
