Development of two fully automated quick, easy, cheap, effective, rugged, and safe pretreatment methods for the extraction of psychotropic drugs from whole blood samples

Quick, easy, cheap, effective, rugged, and safe extraction strategies are becoming increasingly adopted in various analytical fields to determine drugs in biological specimens. In the present study, we developed two fully automated quick, easy, cheap, effective, rugged, and safe extraction methods based on acetonitrile salting-out assisted liquid-liquid extraction (method 1) and acetonitrile salting-out assisted liquid-liquid extraction followed by dispersive solid-phase extraction (method 2) using a commercially available automated liquid-liquid extraction system. We applied these methods to the extraction of 14 psychotropic drugs (11 benzodiazepines and carbamazepine, quetiapine, and zolpidem) from whole blood samples. Both methods prior to liquid chromatography-tandem mass spectrometry analysis exhibited high linearity of calibration curves (correlation coefficients, > 0.9997), ppt level detection sensitivities, and satisfactory precisions (< 8.6% relative standard deviation), accuracies (within +/- 16% relative error), and matrix effects (81-111%). Method 1 provided higher recovery rates (80-91%) than method 2 (72-86%), whereas method 2 provided higher detection sensitivities (limits of detection, 0.003-0.094 ng/mL) than method 1 (0.025-0.47 ng/mL) owing to the effectiveness of its dispersive solid-phase extraction cleanup step. These fully automated extraction methods realize reliable, labor-saving, user-friendly, and hygienic extraction of target analytes from whole blood samples.