Finally, optimal extraction conditions were obtained using the desirability function of the statistical software. The optimal conditions to extract EDCs from milk samples with the aid of MSPE were: 17 mg of Fe3O4@SiO2@C18 as sorbent and 2.3 mL n-hexaneas elution solvent, for an elution time of 4 min. Under optimal conditions, the model predicted maximum total extraction profitability of 97%. In order to verify the accuracy of the model, three
additional experiments were conducted, under optimal conditions. The experimental average recovery obtained was 93%, which was in good agreement with the predictive value, indicating the adequacy of the response model for the extraction process.