巯基化衍生结合分散液相微萃取-气相色谱/串联质谱-选择反应监测技术测定尿样中超痕量氯乙烯基胂酸

目的：建立路易氏剂染毒尿样中超痕量氯乙烯基胂酸（CVAOA）的分析检测方法。方法采用正交实验，优化分散液相微萃取（DLPME）条件，优化结果为：将250μl甲醇（分散溶剂）、250μl乙酸乙酯（萃取溶剂）、3，4-二巯基甲苯（DMT）（衍生试剂，用量满足摩尔比CVAOA∶DMT=1∶100）混合液，加入到pH=1的1 ml尿样中，90℃衍生并萃取60 min，使用气相色谱/串联质谱-选择反应监测模式〔GC/MS/MS（SRM）〕对衍生产物进行定性定量分析。结果本法在50 pg/ml~1μg/ml浓度范围内呈现良好的线性（r2=0.9999），相对标准偏差（RSD）＜10%，检出限可达18 pg/ml，定量限为56 pg/ml，远低于已报道的DLPME分析方法。对低、中、高3种浓度（0.5、5和50 ng/ml）的路易氏剂染毒尿样进行检测，准确度为98.2%~104%，RSD为6.9%~8.9%。结论本文所建方法灵敏度高，专属性好，准确度和精密度良好，且操作简单，适用于真实染毒样品分析。

Determination of ultra-trace 2-chlorovinylarsonic acid in human urine by GC/MS/MS(SRM)after thiolation and dispersive liquid-phase microextraction

Objective To develop a method for determination of ultra-trace 2-chlorovinylarsonic acid(CVAOA)in human urine specific to lewisite exposure. Methods The conditions for dispersive liquid-phase microextraction(DLPME)were optimized by orthogonal experiments with results as follows:a mixture of 250μl methanol(dispersive solvent),250μl ethyl acetate(extraction sol?vent),and 3,4-dimercaptotoluene(DMT)(derivatization reagent,using 1∶100 mole ratio of CVAOA to DMT)was injected into 1 ml urine when pH was adjusted to 1. In the next 60 min,the CVAOA was derivated and the CVAOA-DMT derivative was extracted simul?taneously at 90℃. The derivative was then analyzed by gas chromatography/tandem mass spectrometry-select reaction monitoring〔GC/MS/MS(SRM)〕. Results The linear calibration extended from 50 pg/ml to 1μg/ml(r2=0.9999)with the relative standard deviations (RSD)less than 10%. The limit of detection was 18 pg/ml and the limit of quantitation was 56 pg/ml,which was much lower than that of the reported DLPME methods. When detecting human urine samples with low,middle and high spiked concentrations(0.5,5 and 50 ng/ml)of lewisite,the analysis accuracies ranged from 98.2%to 104%and the RSD ranged from 6.9%to 8.9%. Conclusion The method developed in this study has high specificity and sensitivity as well as good precision and accuracy. It is s imple and can be readi?ly applied to the exposed sample analysis.