Rapid drug extraction from human whole blood using a modified QuEChERS extraction method

A modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) has been developed for the simultaneous determination of forensically important drugs and poisons (more than 90 compounds) in human whole blood. Because the QuEChERS method is commonly used for the analysis of pesticide residues in foods, we customized the QuEChERS method for forensic use. This extraction method consists essentially of two steps: (1) extraction/partitioning and (2) dispersive-solid phase extraction. In step 1, three-fold diluted blood was mixed with an internal standard (D5-diazepam for basic drugs or D5-phenobarbital for acidic drugs) solution, a QuEChERS pre-packed extraction kit (containing magnesium sulfate and sodium acetate) and a stainless steel bead, then partitioned into three layers by centrifugation. In step 2, the top layer (acetonitrile) was transferred into a centrifuge tube containing a dispersive-solid phase sorbent (containing primary secondary amine, end-capped octadecylsilane, and magnesium sulfate) and mixed for purification. After the centrifugation, supernatant was injected into LC–MS/MS. The QuEChERS method was applied in an autopsy case and we confirmed that this method can easily extract various types of drugs and metabolites from human whole blood. The combination of the modified QuEChERS method and LC–MS/MS could enable technicians inexperienced in forensic toxicological analysis to acquire reliable data quickly and easily.