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

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 1048; pp. 77 - 84
• Main Authors: Vårdal, Linda, Askildsen, Hilde-Merete, Gjelstad, Astrid, Øiestad, Elisabeth Leere, Edvardsen, Hilde Marie Erøy, Pedersen-Bjergaard, Stig
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 24.03.2017
• Subjects: Chromatography, High Pressure Liquid - methods; Equipment Design; Humans; Hydrogen-Ion Concentration; Limit of Detection; Liquid-Liquid Extraction - instrumentation; Liquid-Liquid Extraction - methods; Liquid-phase microextraction; Membranes, Artificial; New psychoactive substances; Parallel artificial liquid membrane extraction; Plasma samples; Psychotropic Drugs - blood; Psychotropic Drugs - isolation & purification; Tandem Mass Spectrometry - methods; Whole blood samples; Whole blood samples; Liquid-phase microextraction; New psychoactive substances; Plasma samples; Parallel artificial liquid membrane extraction
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2017.02.010

•Screening of new psychoactive substances (NPS) in plasma and whole blood was performed using parallel artificial liquid membrane extraction (PALME).•PALME was performed with commercially available 96-well plates.•The extracts were analyzed by LC–MS/MS.•PALME provided extensive sample clean-up, possibility for high throughput, a simple workflow, low solvent consumption, and aqueous extracts that were directly compatible with LC–MS.•Method validation was satisfactory, and PALME is expected to be a valuable tool in forensic laboratories in the near future. 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.