Ramírez Fernández María Del Mar, Wille Sarah M R, Di Fazio Vincent, Samyn Nele
Federal Public Service Justice, National Institute of Criminalistics and Criminology, Brussels, Belgium.
Federal Public Service Justice, National Institute of Criminalistics and Criminology, Brussels, Belgium.
Forensic Sci Int. 2019 Apr;297:277-283. doi: 10.1016/j.forsciint.2019.02.027. Epub 2019 Feb 21.
Since gamma-hydroxybutyric acid (GHB) is present in hair of the general population under physiological concentrations, special attention has to be given to the hair analysis of GHB and its interpretation. Normal levels of endogenous GHB can vary in each individual. As a result, strands of hair from a subject have to be cut in small segments (0.3-0.5 cm long) with analysis of each segment. As such, each subject can be used as its own control with a continuous endogenous signal. If one segment has a GHB concentration 10 times higher than the others, this suggests possible administration of exogenous GHB according to the UNODC guideline for Drug Facilitated Assault Cases.
As cosmetic treatments were found to decrease drug concentrations in hair, the aim of the study was to develop an UPLC-MS/MS method for the analysis of GHB in hair. An in vitro study was then carried out in order to evaluate the impact of a hair straightener or a bleaching treatment on endogenous GHB concentrations.
Hair samples (10 mg) were washed with dichloromethane and water. After drying overnight in an oven at 35 °C the samples were pulverized in disposable plastic tubes. Methanol/acetonitrile/ammonium formate buffer 1 mM (25:25:50, v/v/v) was used to extract the drug from the hair matrix in a water bath for 1.5 h at 37 °C. Thereafter, the samples were filtered and evaporated to dryness. The dried extracts were then reconstituted in mobile phase and injected in a UPLC-MS/MS (Waters, Winslow, UK) with a BEH C18 column.
The method was validated using untreated hair samples from three healthy volunteers. The calibration curve ranged from 0.06 to 25 ng/mg and the repeatability and intra-batch precision was lower than 20% evaluated in 8 different batches. Processed samples were stable for 3 days in the auto-sampler. To demonstrate the method applicability, 54 hair samples from healthy volunteers were analysed for endogenous GHB resulting in a concentration range from 0.2 to 6 ng/mg. Three different hair treatments experiments were carried out, in which a hair straightener and/or a bleaching treatment were applied. These experiments demonstrated that hair treatments decreased up to 80% of the GHB endogenous concentrations.
This in vitro study showed that hair bleaching or a heat source treatment influences GHB concentrations in hair. For a correct interpretation of GHB results in hair, cosmetic treatments should be considered, certainly in cases where only a part of the hair is treated.
由于γ-羟基丁酸（GHB）在一般人群头发中以生理浓度存在，因此必须特别关注GHB的毛发分析及其解读。内源性GHB的正常水平在个体之间可能有所不同。因此，必须将受试者的头发剪成小段（0.3 - 0.5厘米长）并对每段进行分析。这样，每个受试者都可以作为自身的对照，具有连续的内源性信号。如果某一段的GHB浓度比其他段高10倍，则根据联合国毒品和犯罪问题办公室（UNODC）关于药物协助攻击案件的指南，这表明可能使用了外源性GHB。
由于发现美容治疗会降低头发中的药物浓度，本研究的目的是开发一种用于分析头发中GHB的超高效液相色谱 - 串联质谱（UPLC-MS/MS）方法。然后进行了一项体外研究，以评估直发器或漂白处理对头发内源性GHB浓度的影响。
将头发样品（10毫克）用二氯甲烷和水洗涤。在35°C的烘箱中过夜干燥后，将样品在一次性塑料管中粉碎。使用甲醇/乙腈/1 mM甲酸铵缓冲液（25:25:50，v/v/v）在37°C的水浴中从头发基质中提取药物1.5小时。之后，将样品过滤并蒸发至干。然后将干燥的提取物用流动相复溶，并注入配备BEH C18柱的UPLC-MS/MS（英国温斯洛的沃特世公司）中。
使用来自三名健康志愿者的未处理头发样品对该方法进行了验证。校准曲线范围为0.06至25 ng/mg，在8个不同批次中评估的重复性和批内精密度低于20%。处理后的样品在自动进样器中可稳定保存3天。为了证明该方法的适用性，对54份来自健康志愿者的头发样品进行了内源性GHB分析，浓度范围为0.2至6 ng/mg。进行了三种不同的头发处理实验，其中应用了直发器和/或漂白处理。这些实验表明，头发处理可使GHB内源性浓度降低高达80%。
这项体外研究表明，头发漂白或热源处理会影响头发中的GHB浓度。为了正确解读头发中GHB的结果，应考虑美容治疗，尤其是在仅部分头发接受处理的情况下。
