B-299 Liquid Chromatography-mass Spectrometry Measurement of Drugs of Abuse and Alcohol Biomarker Phosphatidylethanol (peth 16:0/18:1) Using Volumetric Dried Blood Spot Device

Abstract

Abstract Background Reliable biomarkers have great significance in the investigation of alcohol consumption patterns and in the treatment of alcohol-induced diseases. Direct biomarkers to detect alcohol intake are non-oxidative products of ethanol metabolism (1, 2). Phosphatidylethanol (PEth), blood-based direct alcohol biomarker, represents a group of unnatural phospholipids formed on leukocytes and predominantly erythrocyte membranes. The presence of PEth in blood samples is an indisputable indicator of ethanol consumption (3, 4). Moreover, detecting drugs of abuse (DOA) including opiates, amphetamines, cocaine metabolites, benzodiazepines, THC-metabolites, MDMA, methadone, fentanyl etc. is important to establish patterns of illicit drug usage. In recent years, DBS has been gaining interest in plenty of research areas owing to ease of specimen collection and storage (5, 6).The main objective of this study was to determine the concentration of PEth-16:0 18:1 in DBS samples collected using a volumetric dried blood spot (DBS) device (HemaxisTM DB) and to identify/quantify drugs of abuse (including 119 parameters-Jasem Clinical Toxicology mixture) using another blood spot punch of the same DBS sample. Methods According to Jasem method, DBS samples were prepared by sampling from spiked 20 µL of blood drop located onto paraffin film. PEth-16:0 18:1 and DOA were extracted from entire blood spot of DBS specimens implementing two different extraction reagents at room temperature for 10 min then subjected to HPLC system equipped with Agilent 6470 TQ. The total run times from injection to injection for PEth and DOA were 4.0 min and 12.0 min respectively. Results The linearity and accuracy of the methods were evaluated using 5 DBS calibrators levels for PEth and 6 DBS calibrators levels for DOA. Linearity was confirmed in the range 10 to 1000 ng/mL (r² > 0.995) for PEth 16:0/18:1 and in the range 2 to 100 ng/mL for DOA (r² > 0.99). For two methods linearity, RSD% (inter-intraday) and accuracy were within the analytical acceptable ranges. Conclusion The measurement of blood PEth levels provides a precious tool to determine the chronological profile based on retrospective alcohol intake in a reliable way. Besides, simultaneous analysis of DOA containing 119 parameters ensures comprehensive analytical solution and clinically relevant information. Both of Jasem LC-MS/MS approaches are centred on simple sample preparation following non-invasive sample collection method. Prior to rapid extraction, applying volumetric DBS device assures to collect fixed volume of blood regardless of blood haematocrit level making the measurements more consistent.