为了快速、高效、简便、准确的测定食品中的痕量汞,实验以龙井茶为材料,样品经过微波消解、巯基棉(SCF)分离富集后,以汞离子在酸性溶液和表面活性剂存在的条件下,可与硫代米蚩酮(TMK)形成胶束增溶配合物为基础,建立了微波消解-巯基棉分离富集—表面活性剂增溶分光光度法测定茶叶中痕量汞的方法。结果表明:微波消解功率400 W,消解时间5 min,p H值为4.5,表面活性剂十二烷基苯磺酸钠2 m L,硫代米蚩酮(TMK)2 m L时测定条件最佳;其线性方程为Y=0.037 2X+0.003 1,相关系数r=0.999,经检测龙井中汞的含量为0.013 9 mg/kg,加标回收率为99.91%,RSD为4.0%。

A quick and effective method which is used to detect the heavy metals-mercury in food was established. After microwave digestion and sulfhydryl cotton( SCF) enrichmentand separation of mercury ions in acidic solution,based on the dodecyl benzene sulfonic acid sodium salt react with thiomichler's ketone( TMK) to form micelles solubilization complexes,the microwave digestion-SCF separation and enrichment of micellarsolubilization spectrophotometry method was developed for the determination of Hg2 +in tea. The resolution power of 400 W,digestion time for 5 min,dodecyl benzene sulfonic acid sodium TMK 2 m L at p H 4. 5 was the best condition. The detection of mercury content in longjing tea was 0. 013 9 mg / kg,the linear correlation coefficient was 0. 999,method recovery was99. 91%. The RSD was 4. 0%. The method to improve the selectivity and sensitivity and microwave digestion can save energy and time; it also has little pollution and can decompose samples completely,especially it can avoid the loss of mercury as much as possible. The approach was applied to determine trace amount of Hg in tea.