Swedish National Laboratory of Forensic Science - SKL, SE-581 94 Linköping, Sweden.
Forensic Sci Int. 2011 Jul 15;210(1-3):247-56. doi: 10.1016/j.forsciint.2011.03.016. Epub 2011 Apr 9.
The spontaneous conversion of γ-butyrolactone (GBL) to γ-hydroxybutyric acid (GHB) in seven different Swedish tap waters was investigated. The waters used in the study were selected to represent the diversity among Swedish tap waters as well as possible, which was enabled by principal component analysis (PCA) of a number of water quality parameters. GBL solutions (5, 25 and 50% v/v) were prepared in each of the tap waters and in deionized water and the formation of GHB was followed over time. The GHB quantifications were made using a CZE method, employing a carrier electrolyte consisting of 25mM benzoic acid, 54mM tris(hydroxymethyl)aminomethane (Tris) and 1.7mM tetradecyltrimethylammonium bromide (TTAB), which was developed as a part of the current study. Data evaluation showed that the formation of GHB was largely dependent on the type of tap water. For example, there was a negative correlation between the kinetics of the GHB formation and the alkalinity of the tap waters (r(2)=0.990). This could be explained by a faster decrease in pH in the waters with low buffering capacity (i.e. low alkalinity), which catalysed the hydrolysis of GBL. Equilibrium was reached after 40-250 days depending on the initial GBL concentration and the type of tap water. The level of the equilibrium appeared to be dependent on the initial GBL concentration and ranged from 26 to 37%. Gained knowledge on the levels of the GHB/GBL equilibrium and the kinetics of the formation of GHB in tap water solutions of GBL, including the influence of the tap water quality, may be useful information for casework with the GHB/GBL problem in focus.
研究了七种不同的瑞典自来水对γ-丁内酯（GBL）自发转化为γ-羟基丁酸（GHB）的情况。所使用的水是通过对若干水质参数进行主成分分析（PCA）来选择的，旨在尽可能代表瑞典自来水的多样性。在每种自来水中以及去离子水中制备了 5%、25%和 50%v/v 的 GBL 溶液，并随着时间的推移跟踪 GHB 的形成情况。采用当前研究开发的包含 25mM 苯甲酸、54mM 三羟甲基氨基甲烷（Tris）和 1.7mM 十四烷基三甲基溴化铵（TTAB）的 CZE 方法进行 GHB 定量分析。数据评估表明，GHB 的形成在很大程度上取决于自来水的类型。例如，GHB 形成的动力学与自来水的碱度呈负相关（r²=0.990）。这可以通过低缓冲能力（即低碱度）的水中 pH 值下降更快来解释，这促进了 GBL 的水解。根据初始 GBL 浓度和自来水的类型，平衡在 40-250 天后达到。平衡水平似乎取决于初始 GBL 浓度，范围为 26%至 37%。获得的关于 GBL 自来水溶液中 GHB/GBL 平衡水平和 GHB 形成动力学的知识，包括自来水质量的影响，对于以 GHB/GBL 为重点的案例工作可能是有用的信息。
