Parallel artificial liquid membrane extraction (PALME) was combined with ultra-high performance liquid chromatography-mass spectrometry (UHPLC–MS) and the potential for screening of new psychoactive substances (NPS) was investigated for the first time. PALME was performed in 96-well format comprising a donor plate, a supported liquid membrane (SLM), and an acceptor plate. Uncharged NPS were extracted from plasma or whole blood, across an organic SLM, and into an aqueous acceptor solution, facilitated by a pH gradient.

MDAI (5,6-methylenedioxy-2-aminoindane), methylone, PFA (para-fluoroamphetamine), mCPP (meta-chlorophenylpiperazine), pentedrone, methoxetamine, MDPV (methylenedioxypyrovalerone), ethylphenidate, 2C-E (2,5-dimethoxy-4-ethylphenethylamine), bromo-dragonfly, and AH-7921 (3,4-dichloro-N-{[1-(dimethylamino)cyclohexyl]methyl}benzamide) were selected as representative NPS. Optimization of operational parameters was necessary as the NPS were novel to PALME, and because PALME was performed from whole blood for the very first time. In the PALME method developed for plasma, NPS were extracted from a 250 μL alkalized donor solution consisting of 125 μL plasma sample, 115 μL 40 mM NaOH, and 10 μL internal standard. In the PALME method from whole blood, the 250 μL alkalized donor solution consisted of 100 μL whole blood, 50 μL deionized water, 75 μL 80 mM NaOH, and 25 μL internal standard. In both methods, extraction was accomplished across an SLM of 5 μL dodecyl acetate with 1% trioctylamine (w/w), and further into an acidic acceptor solution of 50 μL 20 mM formic acid. The extraction was promoted by agitation at 900 rpm and was carried out for 120 min. Method validation was performed and the following parameters were considered: linearity, limits of quantification (LOQ), intra- and inter-day precision, accuracy, extraction recoveries, carry-over, and matrix effects. The validation results were in accordance with FDA guidelines.