Standardization of the analytical procedure based on deep eutectic solvent for the extraction and measurement of tricyclic antidepressants drugs in post-mortem blood samples

Abstract

Measuring drugs in post-mortem blood samples is one of the most important challenges in forensic medicine. The development of sensitive analytical techniques for the measurement of drugs in biological samples is of great use in forensic medicine. In this research an easy, safe and environmental friendly vortex-assisted liquid phase microextraction (VA−LPME) based on deep eutectic solvent (DES) followed by high performance liquid chromatography−ultraviolet detector (HPLC−UV) was developed for the extraction, preconcentration and analysis of tricyclic antidepressants drugs (TCAs) in post-mortem blood samples. DES synthesized from thymol as hydrogen bond acceptor (HBA) and ethylene glycol (EG) as hydrogen bond donor (HBD) with a molar ratio of 2:1 was used as an extractant. After adding DES to the sample solution, the resulting mixture was vortexed in order to increase the contact surface and increase the extraction efficiency. Next, phase separation was done using centrifugation. Some effective parameters on the extraction were studied and optimized. Under the optimum conditions, intra- and inter-day %RSDs of the method based on 7 replicate measurements of 100 μg L–1 of TCAs in blood samples were in the range of 2.4–5.1 and 3.7–6.8 %, respectively. The analytical performance of the method showed linearity over the concentration of 3–500 μg L−1 with the detection limits ranging from 1.0–2.0 μg L−1. The trueness of the method was confirmed by spiking different concentrations of TCAs in real blood samples and obtaining relative recoveries in the range of 91.2–108 %.