Determination of tryptamine analogs in whole blood by 96-well electromembrane extraction and UHPLC-MS/MS

Tryptamines are a class of new psychoactive substances relevant for analysis in forensic laboratories. Tryptamine analogs are diverse in structure and chemical properties, and prone to display instability. This puts high demands on sample preparation, especially from complex matrices such as whole blood. In the present paper, a prototype 96-well electromembrane extraction (EME) device was employed for the simultaneous extraction of 20 tryptamines from whole blood prior to UHPLC-MS/MS analysis. For the EME procedure, spiked whole blood diluted 3-fold with 1% ascorbic acid in 25 mM formic acid was extracted for 60 min across a supported liquid membrane (SLM) containing 5% bis(2-ethylhexyl) ether (DEHP) in 2-nitrophenyloctylether (NPOE) into an acceptor solution containing 1% ascorbic acid in 25 mM formic acid. The method was validated for 16 of the tryptamines in the range 5-500 nM according to SWGTOX guidelines and the analytes displayed limits of detection from >0.15 nM to 0.75 nM. An AGREEprep analysis was performed to evaluate method greenness with a final greenness score of 0.76. 96-well EME offered fast, efficient and green extraction of tryptamines from whole blood, demonstrating good potential for implementation in forensic laboratories when commercial devices will become available.