Unit of Forensic Medicine, Department of Diagnostics and Public Health, University of Verona, P.le L.A. Scuro 10, Verona 37134, Italy.
Laboratory of Pharmacokinetics and Metabolomics Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street, Moscow 119991, Russia.
J Anal Toxicol. 2023 Jan 24;46(9):e274-e279. doi: 10.1093/jat/bkac087.
Headspace gas chromatography with a flame ionization detector (HS-GC-FID) is a well-established approach for determining blood alcohol concentration, including in cadaveric specimens. Although the integrity of blood specimens can be adequately guaranteed after the sampling, the quantification of ethanol in cadaveric blood can be affected by postmortem fermentative phenomena occurring between the time since death and the sampling of biofluids. The vitreous humor is less affected by putrefactive phenomena allowing compound determination and its use as an alternative biological matrix. The present work aimed to develop and validate a method using the salting-out effect and based on HS-GC-FID for the determination of ethanol in the vitreous humor. The reported analytical method is based on a simple vitreous humor pre-treatment consisting of a dilution (1:9) with a solution of 2.5 mol/L K2CO3 and 0.0012 mol/L tert-butanol (internal standard). After 1 min of incubation, part of the specimen evaporated in the headspace (2,000 µL) is injected into the chromatographic system and analyzed in isothermal mode (40°C), with a chromatographic time of 1.6 min. The method was validated in terms of selectivity, the lowest limit of detection, intraday and total imprecision, and trueness (bias). The determination of ethanol in the vitreous humor and blood was carried out in 75 cases. The correlation between the two matrices was confirmed in 61 cases. However, 14 vitreous humor specimens showed lower ethanol concentrations, and in the related blood specimens, it was possible to identify the signal of n-propanol, a typical product of postmortem microbial fermentation, that justifies the excess of ethanol in the blood specimens.
顶空气相色谱法-火焰离子化检测器（HS-GC-FID）是一种成熟的方法，用于测定血液中的酒精浓度，包括在尸体标本中。虽然采样后可以充分保证血液标本的完整性，但在死亡后到采集生物体液之间发生的死后发酵现象会影响尸体血液中乙醇的定量。玻璃体液受腐败现象的影响较小，允许进行化合物的测定，并可用作替代生物基质。本研究旨在开发和验证一种使用盐析效应并基于 HS-GC-FID 测定玻璃体液中乙醇的方法。所报道的分析方法基于简单的玻璃体液预处理，包括用 2.5mol/L K2CO3 和 0.0012mol/L 叔丁醇（内标）溶液稀释（1:9）。孵育 1 分钟后，将部分标本蒸发到顶空（2000µL），注入色谱系统并在等温模式（40°C）下分析，色谱时间为 1.6 分钟。该方法在选择性、最低检测限、日内和总精密度以及准确度（偏差）方面进行了验证。在 75 例病例中进行了玻璃体液和血液中乙醇的测定。在 61 例病例中证实了两种基质之间的相关性。然而，14 例玻璃体液标本显示出较低的乙醇浓度，而在相关的血液标本中，可以鉴定出死后微生物发酵的典型产物正丙醇的信号，这解释了血液标本中乙醇过量的原因。
