Canosa P, Rodríguez I, Rubí E, Ramil M, Cela R
Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, Avda de las Ciencias s/n., Santiago de Compostela 15782, Spain.
J Chromatogr A. 2008 Apr 25;1188(2):132-9. doi: 10.1016/j.chroma.2008.02.064. Epub 2008 Mar 7.
An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs.
本文提出了一种测定鱼类和食品样品中三氯生（TCS）和甲基三氯生（MTCS）的改进方法。使用基质固相分散（MSPD）技术同时提取和纯化分析物，然后通过气相色谱-串联质谱（GC-MS/MS）进行选择性测定。测试了分散剂、净化共吸附剂和萃取溶剂的几种组合，以获得无脂提取物以及TCS和MTCS的定量回收率。在优化条件下，将0.5 g样品与1.5 g中性硅胶在研钵中用杵研磨分散，然后转移至装有3 g浸渍有10%硫酸的硅胶（SiO2-H2SO4，10%，w/w）的聚丙烯柱中。用10 mL二氯甲烷回收分析物，而脂质在酸性硅胶层中被氧化。提取物浓缩至干，并用1 mL乙酸乙酯复溶。然后，取0.5 mL馏分与50 μL N-甲基-N-（叔丁基二甲基硅烷基）三氟乙酰胺（MTBSTFA）混合，并注入GC-MS/MS系统。所开发的方法对于低ng g(-1)水平加标的不同样品的绝对回收率在77%至120%之间，定量限在1-2 ng g(-1)范围内，并且与先前开发的样品制备方法相比相当简便。将切片食品样品直接与经TCS处理的厨具表面接触进行的实验表明，这种杀菌剂有迁移到食品中的可能性。
