Simple and rapid analysis of four amphetamines in human whole blood and urine using liquid–liquid extraction without evaporation/derivatization and gas chromatography–mass spectrometry

We developed a simple and rapid analysis method for the determination of four amphetamines in human whole blood and urine using gas chromatography–mass spectrometry (GC–MS). During the course of sample preparation, the evaporation process was found to be the weak point for amphetamine and methamphetamine analysis. Liquid–liquid extraction in this study was conducted without the evaporation step, and the upper solvent layer was injected directly without derivatization, which effectively prevented the volatile amphetamines from vanishing during evaporation and guaranteed the linearity of the calibration curves. This method showed good selectivity, precision, and accuracy, and at the same time was simple and fast. The limits of detection were 5 ng/ml. As an application of this study, a whole blood sample and urine sample from a drug abuse suspect were analyzed. This method may be able to meet the need for rapid and accurate confirmation of positive immunoassay results as well as quantification in clinical and forensic toxicological cases. To our knowledge, no forensic toxicologists have noted that such a basic and simple method, without evaporation or derivatization, is useful for routine analysis of amphetamines using GC–MS.