Extraction-chromatographic determination of narcotic drugs and psychotropic substances in objects of complex matrix composition

Abstract

A comparison of the capabilities of two methods for extraction-chromatographic determination of narcotic drugs and psychotropic substances in various objects (syrups, ointments, tablets, herbal mixtures, etc.), the screening methanol method commonly used in the practice of customs and forensic examination and the proposed extraction method based on the use of water phase (in particular, water solutions of salts) for preliminary effective separation of analytes from matrix components was made. In extraction systems of hexane–water, hexane–aqueous solutions of inorganic salts (sodium chloride, dipotassium phosphate and potassium carbonate), chloroform–water, the method of gas chromatography – mass spectrometry was used to determine the distribution constants (P) of organic bases – narcotic drugs and psychotropic substances (N-methylephedrine, methamphetamine, amphetamine, methadone, dihydrocodeine, hydrocodone, oxycodone, ketamine, cocaine zolpidem, fentanyl, harmine, harmaline). Based on the obtained extraction characteristics of analytes and matrix components, the optimal extractants and extraction conditions, which ensure the maximum efficiency of separation of analytes and matrix components, as well as the concentration of the analyte were substantiated. The use of extraction using water and aqueous solutions of salts provides both a sharp decrease in the detection limit (from 10–3 to 10–7 mol/dm3) in comparison with the methanol method and stable working of chromatographic equipment due to the removal of thermally unstable matrix components was shown.