# Emerging Trends in Pharmacotoxicological and Forensic Sample Treatment Procedures
###### Abstract  
One of the most discussed topics concerns the sample preparation before the analysis and, therefore, all the operations necessary to eliminate the interferents, clean up the specimens, and extract the analytes of interest, reducing the matrix effect. This review highlights the fundamental steps in the treatment of postmortem samples used in forensic analysis. Through critical literature research, it was possible to choose among the countless works that could provide a general overview of the state-of-the-art in this field. Different biological matrices have been considered; blood and urine (the traditional biological fluids) are used to investigate the presence of substances that may have caused death, whilst other body fluids, such as bile and oral fluids, are still under discussion for their usability (and suitability). In the second part of the review, all the solid matrices obtained after autopsy were further divided into conventional and unconventional matrices to facilitate proper understanding. The choice of literature was also made according to the most widely used pretreatment techniques and the most representative innovative techniques.  
post-mortem; sample preparation; forensic analysis; biological matrices; matrix effects 20231328361328331  
used in forensic analytical chemistry are gas chromatography mass spectrometry (GC-MS), gas chromatography tandem mass spectrometry (GC-MS/MS), high-performance liquid chromatography mass spectrometry (HPLC-MS), high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) and tandem mass spectrometry (UHPLC-MS/MS) [4,5]. However, to increase the sensitivity of determination, an appropriate sample pretreatment is necessary to remove the interference(s) of the matrix, extract, and concentrate the analytes to reduce the matrix effects [6]. In forensic toxicology, drug tests have traditionally been performed in whole blood, plasma, and urine specimens considered as \"conventional\" biological fluids [7].  
Sometimes it is not convenient to use blood samples in case of suspected postmortem redistribution, a phenomenon much studied in recent years, which can cause false results [8,9]. For this reason, it is increasingly common to use other biological matrices like vitreous humor, muscle, bile, liver, brain, stomach, and oral fluid. Occasionally, hair, nails, and bone are also used primarily in scenarios of severe decomposition or cruel death where the integrity of the cadaver is severely compromised [10].  
Over the years, different techniques have been developed to maximize the efficiency of extraction and the accuracy of the analysis. Some of these are protein precipitation (PP), liquid-liquid extraction (LLE), and solid-phase extraction (SPE), which are relatively laborious, solvents- and time-consuming [11, 12, 13, 14, 15]. To obtain a fast and precise extraction, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) approach is preferred and has been applied to several forensic samples [16, 17, 18, 19]. Novel strategies for sample preparation, such as microextraction by packed sorbent, solid phase microextraction, polymer monolith microextraction, and more, have already been discussed in the literature [6]. This review aims to overview the information to bring out the use of the most effective extraction techniques in samples consisting of a wide range of complex biological matrices obtained after the autopsy in the field of forensic toxicology.