De Alwis G K Hemakanthi, Needham Larry L, Barr Dana B
Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, NE, Atlanta, GA 30341, USA.
Talanta. 2009 Jan 15;77(3):1063-7. doi: 10.1016/j.talanta.2008.08.007. Epub 2008 Aug 23.
We developed an analytical method based on solid phase extraction, on-support derivatization and isotope dilution-GC/MS for the detection of dialkyl phosphate (DAP) metabolites, dimethyl thiophosphate, diethyl thiophosphate, dimethyl dithiophosphate, and diethyl dithiophosphate in human urine. The sample preparative procedure is simple and fully automated. In this method, the analytes were extracted from the urinary matrix onto a styrene-divinyl benzene polymer-based solid phase extraction cartridge and derivatized on-column with pentafluorobenzyl bromide. The ester conjugated analytes are eluted from the column with acetonitrile, concentrated and analyzed. Compared to extraction-post extraction derivatization methods for the analysis of DAP metabolites, this on-support derivatization is fast, efficient, and less labor-intensive. Furthermore, it has fewer steps in the sample preparation, uses less solvent and produces less interference. The method is highly sensitive with limits of detection for the analytes ranging from 0.1 to 0.3 ng/mL. The recoveries were high and comparable with those of our previous method. Relative standard deviation, indicative of the repeatability and precision of the method, was 1-17% for the metabolites.
我们开发了一种基于固相萃取、柱上衍生化和同位素稀释-气相色谱/质谱联用的分析方法，用于检测人尿中的磷酸二烷基酯（DAP）代谢物、甲基硫代磷酸酯、乙基硫代磷酸酯、二甲基二硫代磷酸酯和二乙基二硫代磷酸酯。样品制备过程简单且完全自动化。在该方法中，分析物从尿液基质中萃取到基于苯乙烯-二乙烯基苯聚合物的固相萃取柱上，并用五氟苄基溴进行柱上衍生化。酯共轭分析物用乙腈从柱上洗脱，浓缩并进行分析。与用于分析DAP代谢物的萃取-萃取后衍生化方法相比，这种柱上衍生化快速、高效且劳动强度较小。此外，它在样品制备中的步骤更少，使用的溶剂更少，产生的干扰也更少。该方法具有高灵敏度，分析物的检测限为0.1至0.3 ng/mL。回收率很高，与我们之前的方法相当。代谢物的相对标准偏差为1-17%，表明该方法的重复性和精密度。
