Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, Universidad de Salamanca, Plaza de los Caídos s/n, 37008 Salamanca, Spain.
J Chromatogr A. 2010 Jul 23;1217(30):4883-9. doi: 10.1016/j.chroma.2010.05.041. Epub 2010 May 31.
A method based on QuEChERS extraction is proposed for the determination of trihalomethanes (chloroform, bromodichloromethane, dibromocloromethane and bromoform) in soil samples. The new version of QuEChERS adapted to soil samples consists of liquid extraction with ethyl acetate, the addition of water to moisten the samples, salting-out partitioning of the water with anhydrous MgSO4, and direct injection of the organic extract, obtained after the centrifugation step, into the gas chromatograph. This simplified extraction procedure maintains the advantages of the original method and avoids some steps, making the final procedure simpler, faster, and cheaper, with the consequent reduction in errors associated with sample manipulation. The experimental conditions of the analytical method, based on fast gas chromatography (FGC) and micro-electron capture detection (microECD), were optimized. The column and oven program used allowed fast separation of the compounds in less than 4 min and the total analysis cycle time was as short as 10 min. The existence of a matrix effect was checked and the analytical conditions of the method were studied in a fortified garden soil sample. The highly sensitive and selective detector used afforded to detection limits in the order of ng/kg for the target compounds. To validate the proposed method two certified reference materials (CRMs) were analyzed.
本文提出了一种基于 QuEChERS 提取的方法，用于测定土壤样品中的三卤甲烷（氯仿、溴二氯甲烷、二溴氯甲烷和溴仿）。适应土壤样品的 QuEChERS 新版本包括用乙酸乙酯进行液液萃取，加水润湿样品，用无水硫酸镁进行盐析分配，以及直接将离心步骤后获得的有机提取物注入气相色谱仪。这种简化的提取程序保留了原始方法的优点，并避免了一些步骤，使最终程序更简单、更快、更便宜，从而减少了与样品处理相关的错误。基于快速气相色谱（FGC）和微电子俘获检测（microECD）的分析方法的实验条件进行了优化。所使用的柱和炉程序允许在不到 4 分钟的时间内快速分离化合物，总分析循环时间短至 10 分钟。检查了基质效应的存在，并在加标花园土壤样品中研究了方法的分析条件。所用的高灵敏度和选择性检测器可达到目标化合物的 ng/kg 级检测限。为了验证所提出的方法，分析了两种认证参考物质（CRMs）。
