直接测汞法在各类型食品分析中的应用研究

Application of method of directly determining mercury in food

目的:使用直接测汞仪测定食品汞,掌握不同种类食品的测定条件。方法:将各种食品置于镍或石英样品舟中,在100℃～300℃进行干燥及预炭化,800℃～950℃灰化,汞经金齐化管富集,样品分解完成后瞬间加热破坏汞齐,汞蒸气进入比色池,直接测定样品中汞的含量,分析操作采用仪器全程控制。通过分析标准样品来考察方法准确性、精密度及适用性。结果:两种标准物质的汞测定值均在给定值范围内,CV分别为3.2%和5.4%。连续4个月采用直接测定法检测某固体胶囊型保健食品,测定结果均值8.47～8.56μg/kg(n=6),CV为2.2%～3.9%(n=6)。结论:该方法准确度和精密度高,检测限可达0.01 ng。与国家标准方法(GB/T5990.17-2003)比较,解决了样品前处理过程中的损失问题,大幅缩短了食品中汞的分析周期,在食物中毒等公共卫生突发事件的检测中具有良好的应用前景。

Objective：To master the optimal analytical procedure for direct determination of mercury in different kinds of food stuff. Methods：Food samples were placed in the nickel or quartz sampling boat and heated to 100℃ -300℃ for drilling and carbonized,800℃ -950℃ for cineration. Mercury was volatilized through the collect tube and gathered together with gold during heating procedures. When the sample was decomposed completely, the mercury - gold amalgam was broken immediately. Mercury vapor, which entered the coloriometric tube could be controlled through in whole distance by the instrument. The veracity, precision and applicability of this method were inspected by analyzing the standard samples. Results：Two kinds of standard samples were detected by the direct determination method. The concentration of mercury in the standard samples matched the extent of the reference data. The coefficient variation （CV） was 3.2% - 5.4%. A solid capsule type function food sample was continuously detected for 4 months, and the mercury concentration in it was 8.47 - 8.56 μg/kg（ n = 6 ）, the coefficient variations （CV） were 2. 2% -3.9% （n = 6）. Conclusion：The veracity and precision of the direct determination method of mercury in food are reliable. The detected limit can extend to 0. 01 ng. Compared with the national standard GB/T5009. 17 -2003 ,the direct determination method can solve the mercury losing problem in the handling process and reduce the analytical period obviously. This method has good applied foreground in the determination of mercury in the accidental affairs of the public health.