不同温度保存血痕中EtG、EtS 的稳定性研究

目的建立血痕(DBS)中乙基葡萄糖醛酸苷(EtG)、硫酸乙酯(EtS)液相色谱-串联质谱(LC-MS/MS)的检测方法,研究不同温度保存血痕中EtG、EtS的分解规律,应用于乙醇相关案件的法医学鉴定。方法采集8名志愿者酒后静脉血并制成血痕,均分为3组,分别保存在20℃、4℃、-20℃温度下,于保存当时(0d)、5d、9d、14d、20d、23d、26d、44d、50d,采用多反应离子监测、液相色谱-串联质谱法检测血痕中EtG、EtS的含量。结果血痕中EtG、EtS在10ng/ml^1μg/ml之间线性范围良好,相关系数(r)≥0.998,最低检出限分别为40ng/ml、20ng/ml。不同温度保存血痕中EtG、EtS的含量均呈下降趋势,其中20℃分解最快,-20℃分解最慢,且EtS的检测时限较EtG长。结论在乙醇相关案件的法医学鉴定中,应注意将血痕冷冻(-20℃)保存、及时送检,同时检测其中EtG、EtS的含量,避免假阴性结果的出现。

Study on the stability of EtG and EtS in dried blood spots preserved at different temperatures

Objective To establish a method for determining the ethyl glucuronide(EtG)and ethyl sulfate(EtS)by LC-MS/MS to study on the stability of EtG and EtS in dried blood spots(DBS)preserved at different temperatures and apply it to forensic identification of ethanol-related cases.Methods The venous blood of 8 volunteers was collected after drinking and made into DBS,which were all divided into three equal groups and preserved at 20℃,4℃,-20℃respecitively.The concentrations of EtG and EtS in above samples were detected by LC-MS/MS with MRM at 0d,5d,9d,14d,20d,23d,26d,44d,50d.Results The calibration curves of EtG and EtS were linear in the concentration range of 10ng/ml^1μg/ml,the correlation coefficient(r)were all more than 0.998,the lower limit of detection were 40ng/ml and 20ng/ml respectively.The concentrations of EtG and EtS in DBS were all in a downward trend at different temperatures,of which the decomposition was the fastest at 20℃and slowest at-20℃.The detection time of EtS was longer than that of EtG.Conclusion Care should be taken to keep DBS used for forensic identification of the ethanol-related cases frozen(-20℃)and submit them for analysis as soon as possible.and meanwhile,detect the concentrations of EtG and EtS to avoid false negative results.