Parallel artificial liquid membrane extraction of new psychoactive substances in plasma and whole blood.

Parallel artificial liquid membrane extraction (PALME) combined with ultra-high performance liquid chromatography-mass spectrometry can screen for new psychoactive substances (NPS) in plasma and whole blood. Eleven NPS, including MDAI, methylone, and MDPV, were extracted from alkalized donor solutions across an organic liquid membrane into an acidic acceptor solution using a pH gradient. For plasma, the donor solution contained 125 µL plasma, 115 µL 40 mM NaOH, and 10 µL internal standard; for whole blood, it contained 100 µL blood, 50 µL water, 75 µL 80 mM NaOH, and 25 µL internal standard. Extraction used 5 µL dodecyl acetate with 1% trioctylamine as the membrane and 50 µL 20 mM formic acid as the acceptor, agitated at 900 rpm for 120 minutes. Validation met FDA guidelines.

Study at a glance

Abstract

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 250μL alkalized donor solution consisting of 125μL plasma sample, 115μL 40mM NaOH, and 10μL internal standard. In the PALME method from whole blood, the 250μL alkalized donor solution consisted of 100μL whole blood, 50μL deionized water, 75μL 80mM NaOH, and 25μL internal standard. In both methods, extraction was accomplished across an SLM of 5μL dodecyl acetate with 1% trioctylamine (w/w), and further into an acidic acceptor solution of 50μL 20mM formic acid. The extraction was promoted by agitation at 900rpm and was carried out for 120min. 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.