In vitro formation of ethanol in autopsy samples containing fluoride ions

Ethanol concentrations in various biological specimens: Living and postmortem forensic toxicology analysis and comprehensive literature review

Alcohol use upsurges the risk for many chronic ill-health consequences such as hepatitis, malignancies, and disastrous outcomes like road traffic accidents ending in fatal injuries. Biochemical and toxicological analysis of different body fluids is crucial for identifying the cause of death and postmortem interval in many forensic cases. Blood, urine, and vitreous fluid are the most valuable body fluids for detecting alcohol during any toxicological analysis. Alcohol is responsible for widespread morbidity and mortality worldwide. Blood alcohol concentration (BAC) is a necessary toxicological test to investigate various crime and accident scenes. This study comprehensively explores the demographic characteristics, BAC distribution, and correlations of alcohol concentrations in postmortem and living cases. Postmortem cases (N = 166) reveal intriguing demographic patterns, with notable variations in year distribution, nationality, sex, age groups, occupation, smoking habits, place of death, and psychiatric history. Living cases (N = 483) exhibit distinct demographic profiles, emphasizing differences in year distribution, nationality, sex, age groups, and smoking habits. Analysis of BAC distribution reveals diverse patterns in both postmortem and living cases, providing valuable insights into the prevalence of different BAC levels in each group. Correlation analyses unveil strong associations between alcohol concentrations in various biological samples in postmortem cases, highlighting the interdependence of blood, vitreous, and urine alcohol concentrations. Conversely, living cases display a moderate positive correlation between blood and urine alcohol concentrations. Comparative analyses showcase significant differences in mean alcohol concentrations between postmortem and living cases, suggesting variations in alcohol metabolism and distribution. These findings underscore the importance of considering temporal factors in interpreting alcohol concentrations in forensic and clinical contexts. In conclusion, this study enhances our understanding of alcohol-related incidents by delineating demographic profiles, BAC distributions, and correlations between different biological samples. Such insights are crucial for refining investigative and clinical approaches, contributing to the broader fields of forensic science and public health.

Evaluation of the Compatibility of Ethyl Glucuronide and Ethyl Sulphate Levels to Assess Alcohol Consumption in Decomposed and Diabetic Postmortem Cases

The aim of the study is to evaluate the contribution of ethanol metabolite detection in postmortem cases by showing the connection between the presence of ethanol metabolites, which are indicators of alcohol consumption, and the detection of potential postmortem ethanol formation in decomposed and diabetic cases. Determination of ethanol consumption before death is often one of the most important questions in death investigations. Postmortem ethanol formation or degradation products in the blood make it difficult to distinguish antemortem consumption or postmortem formation of ethanol and eventually may lead to misinterpretation. Decomposed bodies and diabetic cases are vulnerable to postmortem ethanol formation due to putrefaction, fermentation or other degradations. Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are two metabolites of ethanol produced only in the antemortem time interval. In this study, EtG and EtS levels in urine and vitreous humor samples of 27 postmortem cases, including diabetic and degraded bodies were compared to ethanol results of their blood, urine, and vitreous humor samples. EtG and EtS in urine and vitreous humor were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and ethanol was assayed by routine headspace gas chromatography-flame ionization detector (GC-FID). These cases were devoid of other influences from forensically relevant drugs, so ethanol and/or glucose were among the only positive findings in these cases. The results of this pilot study indicate the postmortem ethanol concentrations do not correlate with the measured EtG and EtS values but are beneficial in rulings of accidental or natural deaths. This preliminary study gives additional data to help distinguish between antemortem ethanol intake and postmortem formation. EtG and EtS were well correlated positively with antemortem ethanol use instead of forming spontaneously in samples from decedents who are decomposing or have a history of diabetic hyperglycemia.

Microbial neoformation of volatiles: implications for the estimation of post-mortem interval in decomposed human remains in an indoor setting

The objective of this study was to determine if a relationship between microbial neoformation of volatiles and the post-mortem interval (PMI) exists, and if the volatiles could be used as a tool to improve the precision of PMI estimation in decomposed human remains found in an indoor setting. Chromatograms from alcohol analysis (femoral vein blood) of 412 cases were retrospectively assessed for the presence of ethanol, N-propanol, 1-butanol, and acetaldehyde. The most common finding was acetaldehyde (83% of the cases), followed by ethanol (37%), N-propanol (21%), and 1-butanol (4%). A direct link between the volatiles and the PMI or the degree of decomposition was not observed. However, the decomposition had progressed faster in cases with microbial neoformation than in cases without signs of neoformation. Microbial neoformation may therefore act as an indicator of the decomposition rate within the early decomposition to bloating stages. This may be used in PMI estimation based on the total body score (TBS) and accumulated degree days (ADD) model, to potentially improve the model's precision.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

Stability of Ethyl Glucuronide, Ethyl Sulfate, Phosphatidylethanols and Fatty Acid Ethyl Esters in Postmortem Human Blood

The lack of systematic studies on the stability of ethanol's non-oxidative metabolites in postmortem specimens restricts their use in forensic cases. This study aimed to compare the stability of ethyl glucuronide (EtG), ethyl sulfate (EtS), phosphatidylethanols (PEths) and fatty acid ethyl esters (FAEEs) in postmortem human blood. Three groups were established based on the level and source of ethanol: the blank group, the ethanol-spiked group and the ethanol-positive group. Each group contained six blood samples from different corpses. The samples in each group were placed at 37, 25, 4 and -20°C. Every 24 h for 7 days, 50 μL was collected from each sample. The levels of EtG, EtS, PEths and FAEEs were determined by liquid chromatography-mass spectrometry, and their stability was evaluated. EtG was not detected in the blank group, but it was found in samples in the ethanol-spiked group placed at 37°C, and it was degraded in the ethanol-positive group at 37 and 25°C. EtS showed no change in any of the groups. PEths were not detected in the blank group, but formation was found in the ethanol-spiked group at all temperatures. In the ethanol-positive group, PEth levels fluctuated at 37°C, decreased at 25°C and increased at -20°C. FAEEs were generated in the blank group and in the ethanol-spiked group at all temperatures. In the ethanol-positive group, FAEEs were degraded at 37 and 25°C but were generated at 4 and -20°C. EtS is a reliable biomarker of ethanol consumption, and EtG could be used as a biomarker at low temperatures (4 and -20°C), but PEths and FAEEs are not appropriate biomarkers of ethanol consumption.

EtG and EtS in Autopsy Blood Samples With and Without Putrefaction Using UPLC-MS-MS

Analytical challenges related to postmortem specimens are well known. The degree of putrefaction of the corpse will influence the quality of the blood samples, and both the efficiency of sample preparation and the subsequent chromatographic performance can be affected. An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method was developed and validated for the determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in postmortem whole blood. Sample preparation prior to UPLC-MS-MS analysis consisted of protein precipitation and filtration through a phospholipid removal plate. Chromatography was achieved using an HSS T3 column and gradient elution with formic acid in water in combination with methanol. The injection volume was 0.5 µL. Negative electrospray ionization was performed in the multiple reaction monitoring mode. Two transitions were monitored for the analytes and one for the internal standards. The between-assay relative standard deviations were in the range of 1.7-7.0% and the limits of quantification were 0.025 and 0.009 mg/L for EtG and EtS, respectively. Recovery was 51-55% and matrix effects ranged from 98% to 106% (corrected with internal standard). Blood samples from nine autopsy cases with various extents of putrefaction were analyzed. The sample preparation efficiently removed the phospholipids from the blood specimens. The samples were clean and the analytical quality of the chromatographic performance was satisfactory for both analytes irrespective of the degree of putrefaction.

Best-practices approach to determination of blood alcohol concentration (BAC) at specific time points: Combination of ante-mortem alcohol pharmacokinetic modeling and post-mortem alcohol generation and transport considerations

Alcohol concentrations in biological matrices offer information regarding an individual's intoxication level at a given time. In forensic cases, the alcohol concentration in the blood (BAC) at the time of death is sometimes used interchangeably with the BAC measured post-mortem, without consideration for alcohol concentration changes in the body after death. However, post-mortem factors must be taken into account for accurate forensic determination of BAC prior to death to avoid incorrect conclusions. The main objective of this work was to describe best practices for relating ante-mortem and post-mortem alcohol concentrations, using a combination of modeling, empirical data and other qualitative considerations. The Widmark modeling approach is a best practices method for superimposing multiple alcohol doses ingested at various times with alcohol elimination rate adjustments based on individual body factors. We combined the selected ante-mortem model with a suggestion for an approach used to roughly estimate changes in BAC post-mortem, and then analyzed the available data on post-mortem alcohol production in human bodies and potential markers for alcohol production through decomposition and putrefaction. Hypothetical cases provide best practice approaches as an example for determining alcohol concentration in biological matrices ante-mortem, as well as potential issues encountered with quantitative post-mortem approaches. This study provides information for standardizing BAC determination in forensic toxicology, while minimizing real world case uncertainties.

A review of the use of ethyl glucuronide as a marker for ethanol consumption in forensic and clinical medicine

Ethyl glucuronide (EtG) is a direct phase-II metabolite of ethanol formed through the UDP-glucuronosyl transferase catalyzed conjugation of ethanol with glucuronic acid. It has been detected in many antemortem and postmortem biological matrices using a variety of analytical methods. Due to its long urinary elimination time, detectability in hair, specificity for ethanol exposure, and low detection limits of assays, the use of EtG has been proposed as a marker of recent ethanol intake in a variety of clinical and legal settings, including medical monitoring for relapse, emergency department patient evaluation, postmortem assessments, and transportation accident investigation. However, challenges associated with factors such as establishing appropriate cut-off levels capable of distinguishing between drinking and nonbeverage sources of ethanol exposure, nonuniform laboratory reporting limits, sample stability, and microbial activity substantially complicate accurate interpretation of results. The following review briefly explores the history, utility, and limitations of EtG in contemporary medical and forensic practice.

Assessment of the stability of the ethanol metabolite ethyl sulfate in standardised degradation tests

Ethyl sulfate (EtS) is a non-oxidative metabolite of ethanol, used for forensic purposes as an ethanol consumption marker in addition to the ethanol metabolite ethyl glucuronide (EtG) which after certain scientific publications is prone to biological degradation. As ethanol is widely consumed in many western cultures, knowledge about the stability of ethyl sulfate against biodegradation is of importance for forensic investigations-where EtS until now was thought to be stable against bacterial degradation. Using standardized test methods from the panel of OECD tests, the stability of EtS against bacterial degradation was assessed in this study. These experiments showed that EtS was stable in the closed bottle test (CBT) (OECD 301 D), but not in the manometric respiratory test (MRT) (OECD 301 F) with higher bacterial density. With respect to forensic investigations the assumption of EtS stability could be disproved and the possibility of bacterial degradation of EtS should be taken into account when alcohol uptake some hours prior to death needs to be ruled out by determination of alcohol consumption markers in putrefied corpses, where ethanol concentration could have been generated post-mortem by fermentation processes.

Was a child poisoned by ethanol? Discrimination between ante-mortem consumption and post-mortem formation

The presence of ethanol in human specimens collected during autopsies is generally considered as an indication of recent ante-mortem alcohol consumption. The interpretation of the results may however be impaired by post-mortem formation of ethanol when microorganisms capable of fermentation of glucose to ethanol are present. Since the distribution in the different fluids and tissues remains contentious to conclude on the origin of the detected ethanol, the determination of specific metabolites of ethanol such as ethyl glucuronide (EtG) may be performed to discriminate between exogenous (ante-mortem) and endogenous (post-mortem). Toxicological analysis of specimens from the autopsy of a child aged 14 months displayed a high concentration of ethanol in blood and tissues. In order to discriminate between ante-mortem alcohol administration and post-mortem formation, the presence of microorganisms capable of ethanol production was checked by fermentation tests and the liver was tested for the presence of EtG and compared with a positive control. Fermentation tests displayed in the blood of the deceased the presence of the bacterial strain Lactococcus garvieae capable of producing ethanol from glucose. The absence of EtG in the liver of the deceased compared to the high level (19.56 mug/g) detected in the positive control's liver is a further indication that the ethanol detected in the body of the deceased is of post-mortem origin.