Rapid and on-site analysis of amphetamine-type illicit drugs in whole blood and raw urine by slug-flow microextraction coupled with paper spray mass spectrometry.

In this study, a slug-flow microextraction (SFME) coupled with paper spray mass spectrometry (PS-MS) method was developed for rapid and on-site analysis of trace amphetamine-type illicit drugs including amphetamine (AM), methamphetamine (MA) and 3,4-methylenedioxy-N-methylamphetamine (MDMA) in complex biological samples such as whole blood and raw urine. The method involved the application of SFME for rapid extraction of trace amphetamine-type illicit drugs from whole blood and raw urine samples, followed by PS for direct MS analysis under ambient and open-air conditions. The experimental parameters including extraction solvent, extraction cycle, high voltage, and spray solvent, etc., were all investigated, and the optimized conditions showed an enhanced sensitivity of 1-2 order of magnitudes compared with PS-MS. The method showed good linearity, with correlation coefficient values (r) of no less than 0.9979 for analysis of AM, MA, and MDMA in human whole blood and raw urine without additional sample pretreatments. The limits of detection and quantification were 0.01-0.05 ng/mL and 0.05-0.2 ng/mL, respectively. Satisfactory recoveries were also obtained, with 74.2-94.9% for whole blood and 80.2-103.6% for raw urine, respectively. All of our experimental results demonstrated that SFME-PS-MS showed great potential for rapid, on-site, in situ, and high-throughput screening of amphetamine-type illicit drugs in various biological samples.