Simultaneous determination of prescription drugs, cocaine, aldicarb and metabolites in larvae from decomposed corpses by LC–MS–MS after solid–liquid extraction with low temperature partitioning

Liquid-liquid and solid-liquid extractions with low-temperature partitioning - A review

The paper represents the first review of solvent extraction techniques utilizing the low-temperature partitioning/purification (LTP) approach. Initially conceived in the 1960s to purify extracts from fatty matrices, it wasn't until the 2000s that this approach received increasing attention for its efficacy in extracting organic compounds from diverse samples, often without additional cleanup steps. This review covers a brief history and proposes a mechanism for LTP-based solvent extraction. Furthermore, the principal practical issues of the technique are spotlighted, elucidating the factors influencing extraction efficiency. The advantages, limitations, and potential combinations with other extraction techniques of the LTP-based solvent extractions are analyzed. The versatility of the LTP approach is demonstrated by its applications in extracting various compounds from food, environmental, and biological samples, emphasizing its potential for rapid sample preparation with minimal steps, few chemicals, and minimal analyst intervention.

Impact of using Sarcophaga (Liopygia) argyrostoma (Robineau-Desvoidy, 1830) as a toxicological sample in detecting clonazepam for forensic investigation

Background

Sarcophagidae along with Calliphoridae (superfamily Oestroidea) were known as important colonizers of cadavers and could be used to estimate the postmortem interval (PMI), through tracking the flies colonizing pattern and/or monitoring their growth rates on cadavers. Many previous researches discussed the impact of toxins in decomposing corpses, on the developmental stages of insects, which would affect the accuracy of PMI estimation. Clonazepam belongs to the benzodiazepines, and it is one of the most routinely used drugs to control humans’ seizures. The current study aimed to investigate the effect of clonazepam on the developmental stages of Sarcophaga argyrostoma, one of the most widespread Sarcophagidae in Giza Governorate. Also, we investigate the ability of these developmental stages to detect the drug.

Results

The current study used different concentrations of clonazepam (25, 50, and 100 mg/ml) as an in vitro application of the flesh fly S. argyrostoma. The drug has affected significantly the morphological measurements (weight, length, and width) of the different developmental stages, especially in the highest concentration (100 mg/ml). Quantitative and qualitative analyses were applied, by using high-performance liquid chromatography-mass spectrometry (HPLC–MS) and protein carbonyls amount respectively, to detect clonazepam in the second, early third, and late third larval instars and prepupa of S. argyrostoma. The results showed that the relationship between the concentration of the drug and its detection in the same developing instar is interdependent, using HPLC–MS. However, the drug faded from instar to the following one and transformed to its metabolite form. Measuring the protein carbonyls amount (OD/mg protein/min) revealed an elevation in the macromolecules damage, compared to the control groups, in almost all treated groups.

Conclusions

The current data suggested that clonazepam has oxidative damage in S. argyrostoma. While HPLC–MS was efficient in measuring the concentration of the drug in the insect, protein carbonyls analysis was a time- and cost-saving method and could be used to detect the drug in insects qualitatively.

Graphical abstract

Unexpected results found in larvae samples from two postmortem forensic cases

Purpose

In forensics, entomological specimens can be used as additional/alternative matrices to detect xenobiotics when human specimens are limited in their application. Despite some advantages over implementing putrefied human remains, most medico-legal laboratories do not include entomotoxicological procedures as routine analytical methods. We thus applied two authentic cases to evaluate necrophagous larvae’s potential as complementary matrices for toxicological analysis after extensive postmortem decomposition.

Methods

Larvae and postmortem human samples, including hair, stomach contents, pericardial fluid, liver, lung, and skeletal muscle, were collected at autopsy. Samples were analyzed by liquid chromatography–tandem mass spectrometry and liquid chromatography–quadrupole time-of-flight mass spectrometry for pharmaceutical substances, illicit drugs, and new psychoactive substances, including synthetic cannabinoids, benzodiazepines, new synthetic opioids, and stimulants.

Results

Nearly all substances detected in human specimens, including several benzodiazepines and synthetic cannabinoids, were also detected in larvae. Surprisingly, some drugs, including the new psychoactive substances EAM-2201 and U-47700, were found exclusively in larvae and hair. The benzodiazepine etizolam was detected only in liver, lungs, and stomach contents, possibly resulting from characteristic tissue distribution in humans and/or larvae.

Conclusions

Antemortem external hair contamination with synthetic cannabinoids from side-stream smoke and postmortem hair contamination with substances in putrefaction fluids can be supposed in these cases. Our findings suggest that supplementary information can indeed be gained from analyzing larvae additional to those human specimens that are typically used for toxicological analysis after extensive postmortem decomposition. Nevertheless, these results represent merely two cases, requiring in-depth studies to determine whether such findings can identify acute intoxications as possible causes of death.

Determination of three cresol isomers in sewage sludge by solid-liquid extraction with low temperature purification and gas chromatography-mass spectrometry

Cresols are chemical contaminants derivative from phenol which can be found in sewage sludge. However, little attention has been given to monitoring these compounds in environmental matrices in the literature. Thus, the objective of this study was to develop a simple method based on solid-liquid extraction with low temperature purification for determining three cresol isomers in sludge. The quantification of these compounds was performed by gas chromatography coupled to mass spectrometry with a previous derivatization step. After a detailed study, the cresol recovery was higher than 91%, with relative standard deviation lower than 12% and a limit of quantification of 20 μg kg^-1. Linearity was achieved between 10 and 90 μg L^-1 (R² > 0.98) with the standard solutions prepared in matrix extracts due to the trouble caused by the matrix effect. The proposed method was applied with success for monitoring cresols in sewage sludge samples coming from six different wastewater treatment plants. All samples showed contamination by cresols, mainly p-cresol with values between 32.3 and 516.9 μg kg^-1. The majority of the analyzed samples showed a total sum of the isomers higher than the maximum residue limit established by Brazilian legislation (160 μg kg^-1).

Forensic entomotoxicology revisited-towards professional standardisation of study designs

Forensic entomotoxicology is the use of insects as evidence of whether a toxicant is present in an environment such as a corpse, river or landscape. The earliest overtly forensic study was published in 1977, and since then, at least 63 papers have been published, most of them focused on the detection of toxicants in insects or on effects of toxicants on diverse insect indicator taxa. A comprehensive review of the published literature revealed various inconsistencies between studies that could be addressed by introducing standard protocols for such studies. These protocols could include selecting widespread and common model organisms (such as Lucilia sericata, Calliphora vicina, Chrysomya megacephala and Dermestes maculatus) and model toxicants (e.g. morphine and amitriptyline) to build up comparative databases; developing a standard matrix for use as a feeding substrate; setting guidelines for statistically adequate sample sizes; and deploying more sophisticated analytical methods from the general field of toxicology. Future studies should then be aimed at refining standardised protocols to improve experimental results, and make these results more comparable between studies.