[Mathematical planning of the liquid-liquid extraction procedure: a forensic chemical study of verapamil in blood].

The objective of the study is to determine the optimal conditions for blood sample preparation by liquid-liquid extraction using mathematical planning of the experiment by the example of forensic chemical study of verapamil. Evaluation of verapamil recovery from blood samples was performed according to the scheme of multivariate three-level experimental planning using the Box-Behnken design. The effect of aqueous phase pH, the ratio of chloroform to n-butanol in the extraction agent, extraction and centrifugation time, addition of sodium chloride, and the ratio of sample and extraction agent volumes on the recovery was studied. The algorithm using mathematical planning and development of liquid-liquid extraction model of target analyte can be recommended for analysis procedure optimization in forensic chemistry.