Simultaneous Determination of Different Classes of Pesticides in Breast Milk by Solid-Phase Dispersion and GC/ECD

This study presents the development, validation and application of a multiresidue analytical method intended to determine nine pesticides and a degradation product (α-endosulfan, β-endosulfan, α-HCH, g-HCH, aldrin, p,p'-DDE, p,p'-DDT, cypermethrin, deltamethrin, and trifluralin) in breast milk samples by solid-phase dispersion and gas chromatography with electron capture detector (GC/ECD). The proposed method is considered simple and efficient, combining extraction and clean up in a single step and quantification performed by standard addition to avoid the matrix effect. The method limits of detection and quantification varied between 0.002 and 0.079 µg mL-1 and 0.013 and 0.108 µg mL-1, respectively. The proposed method was applied to analyze 62 breast milk samples collected between February and June 2010 in Lucas do Rio Verde, Mato Grosso, Brazil. p,p'-DDE (0.32-12.03 µg g-1 of fat), p,p'-DDT (2.62-12.41 µg g-1 of fat) and β-endosulfan (0.54-0.61 µg g-1 of fat) were quantified in 29%, 5% and 3% of the samples, respectively. Aldrin was found below the method quantification limit in 7% of samples. Although these compounds were found in the analyzed samples, mothers were oriented to carry on feeding the infants as the breast milk is considered the optimum food during infancy.