Rapid and simultaneous extraction of acidic and basic drugs from human whole blood for reliable semi-quantitative NAGINATA drug screening by GC–MS

We present a rapid procedure for simultaneous extraction of a wide range of acidic and basic drugs from whole blood samples for reliable semi-quantitative NAGINATA drug screening by gas chromatography–mass spectrometry (GC–MS). To extract a wide range of drugs, the partition/extraction procedure used for the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method was employed as the initial step. Various procedures were tested as the second step for the removal of whole blood impurities, including the use of primary secondary amine and C₁₈ for the dispersive solid-phase extraction of the QuEChERS method, four kinds of silica-based C₁₈ columns, alumina columns, and protein–lipid removal filter cartridges (Captiva ND Lipids). Subsequent GC–MS screening used the NAGINATA software with a constructed calibration-locking database for detection of acidic and basic drugs; drug detection ability, accuracy of tentative concentrations, and drug recoveries were examined and compared. We also examined the applicability of our established method in an actual forensic case. Our results showed that the number of drugs detectable at low concentrations was greatly increased by the use of the partition/extraction procedure of the QuEChERS method as the initial step and the protein–lipid removal filter cartridge as the second step. These combined steps provided notably clean extracts. Recoveries carefully measured with each reference standard were largely more than 60 %, and tentative concentrations obtained by the established screening method without reference standards were in the range of 48–310 % of the expected values for 65 acidic and basic drugs. Therefore, relatively reliable semi-quantitative values were obtained at the screening step without the need for each reference standard. We also experienced significant time savings for the extraction and in obtaining tentative concentrations at the screening step in an actual forensic case, indicating that the method is useful for rapid diagnosis of drug intoxication. Our proposed method should prove useful for semi-quantitative screening of a wide range of drugs and poisons in whole blood samples in clinical and forensic cases.