A novel method for the determination of synthetic cathinones and related substances in postmortem blood samples using cork-based dispersive solid-phase microextraction prior to LC-MS/MS analysis.

Abstract

The detection of new psychoactive substances in postmortem blood is of primary importance for the investigation of related deaths. A method using cork as a biosorbent in a solid-phase microextraction with LC-MS/MS analysis was developed and validated for the determination of synthetic cathinones and related substances in blood. The sample preparation method employed 200 µL of sample and 30 mg of cork powder, and the complete procedure was optimized using multivariate strategies. LC-MS/MS analysis was performed in gradient mode, with a total run time of 7.5 min for the determination of cathinone, ethylone, fentanyl, MDA, MDMA, mephedrone, N-ethylpentylone, and pentylone. Comprehensive validation was performed through the ASB/ANSI Standard 036. Lower limit of quantification (LLOQ) values ranged between 0.5 and 1 ng/mL, with linear ranges between LLOQ and 85 ng/mL. Accuracy and precision results were satisfactory, and significant ion suppression was found (2.9-63.4%). Applicability of the method was evaluated by the analysis of three postmortem blood samples from forensic casework, suspected to have the presence of synthetic cathinones. All samples were positive for MDMA and MDA, with concentrations between 79.2-198.1 ng/mL and 23.1-26.6 ng/mL, respectively. The greenness of the method was also evaluated by AGREEprep, with an overall score of 0.53. This study is the first to apply a cork-based extraction to blood analysis. The method has proven to be reliable and a valuable greener alternative for the determination of synthetic cathinones and related substances in postmortem blood.