Development and validation of an extraction method based on dispersive liquid–liquid microextraction for the analysis by GC–MS of propofol in three different biological samples (blood, urine, and hair). The proposed method is very simple and rapid. Furthermore, the method was applied to both authentic post-mortem and living cases, showing the suitability of this extraction technique for forensic purposes.

ABSTRACT

Propofol is a widely used anesthetic. Although considered safe, propofol-related deaths occur, as it is sometimes abused recreationally or used to commit suicide. A simple, rapid, and reliable method for its analysis in various biological samples is needed. Sample clean-up is a critical step in the analysis, both in terms of time and cost, indeed. Dispersive liquid–liquid microextraction (DLLME) is a simple and fast extraction based on ternary solvent mixtures that uses small volumes of solvent and sample. A DLLME extraction followed by gas chromatography–mass spectrometry (GC–MS) analysis was developed and validated for the analysis of propofol in blood, urine, and hair. The same extraction mixture of 2.5:1 methanol/chloroform was used for the different biological samples. Validation for linearity, LOD, LOQ, precision, accuracy, and recovery gave satisfactory results for the three types of biological samples included in the study, with limits of quantification of 1 μg/mL for urine, 0.2 μg/mL for blood, and 0.1 ng/mg for hair. The DLLME procedure for purification involves a small amount of solvent, thus reducing the cost and the environmental impact. In addition, a high enrichment factor is obtained, and the time for analysis is short. The method was applied to authentic post-mortem samples for the determination of propofol in blood, urine, and hair. Also, segmental hair analysis was performed to assess chronic propofol abuse. The developed method proved to be rapid, simple, and cost-effective for blood, urine, and hair extract clean-up for the determination of propofol by GC/MS.