Of all the drugs plaguing analytical forensic toxicologists, the newer psychoactive substances (NPS) are the most challenging. One of the older NPS’s is the Synthetic Piperazines (SP) class. While circumventing legislative controls, SP’s are encountered as “legal” alternatives to ecstasy. Forensic toxicologists often meet unforeseeable challenges that may delay quantitative analysis of these compounds in biological fluids. Enzymatic reactions, matrix interferences and limited knowledge of analyte stability further complicate interpretation of calculated concentrations in the wide range of matrices submitted to the laboratory for analysis. In a recent paper published in Journal of Analytical Toxicology by Timothy Lau et al., (doi: 10.1093/jat/bkx090) the stability of SP's in human blood under various storage conditions over time was investigated using UCT’s famous flagship sorbent Clean Screen® DAU for the extraction process.

All samples were prepared by spiking certified reference standards of eight SP's into certified drug-free human whole blood independently at 1000 ng/mL as well as mixtures containing all tested SP's in this study. Samples were stored at room temperature (~20°C), 4°C and −20°C for 1, 3, 6, 9 and 12 months in dark sealed containers. Solid phase extraction (SPE) was performed using mixed-mode, Clean Screen® DAU cartridges. After extraction, the analytes were assessed on their degrees of degradation using a UltraFast Liquid Chromatograph coupled to a Tandem Mass Spectrometer (UFLC-ESI-MS/MS) in positive ionization mode.

Of the two categories of SPs, benzyl piperazines were more stable than phenyl piperazines under all storage conditions, in which 1-(4-methylbenzyl)-piperazine (MBZP) had more than 70% (769–1,047 ng/mL) remaining after 12 months. 1-(4-methoxyphenyl)-piperazine (MeOPP) was not detected under room and refrigerated temperatures after 6 months and was the least stable. Matrix interferences and drug–drug interactions were observed.  It is advised that storing biological samples suspected of containing SPs at room temperature should be avoided due to detrimental impacts on stability of the SP compounds. For backlog situations, case samples suspected to contain SPs should be kept frozen or refrigerated even for time periods as short as 30 days for optimal result. Phenyl piperazines stored for more than 6 months showed analyte degradation and loss of parent compounds after extended storage regardless of storage conditions. When forensic toxicologists are faced with the challenges of analyzing NPS compounds, they turn to UCT’s flagship sorbent for the very best results. For more information on Clean Screen® sorbents, applications and methods please visit https://sampleprep.unitedchem.com/products/spe/clinical-forensic/clean-screen-dau