原子荧光光谱法测定食品添加剂碳酸钙中汞

AFS Determination of Mercury in the Food-Additive Calcium Carbonate

采用盐酸(5+95)溶液溶解食品添加剂碳酸钙样品,利用原子荧光光谱法测定碳酸钙试样中汞的含量。优化了灯电流、负高压、原子化器高度、载气及屏蔽气体的流量、载流介质的浓度、硼氢化钾的浓度、共存离子的干扰和消除等试验条件。荧光强度与汞的质量浓度在1.0μg.L-1范围以内呈线性关系,方法的检出限(3s/k)为0.8 ng.L-1,对5.0μg.L-1汞标准溶液进行11次测定的相对标准偏差为0.95%。应用此方法分析了两个碳酸钙试样,以标准加入法做回收试验,平均回收率为103.5%。

Sample of the food-additive,calcium carbonate,was dissolved with HCl（5＋95）,and the content of mercury in the sample solution was determined by AFS.Experimental conditions,including lamp current negative high-voltage,height of atomizer,flow rate of carrier and shielding gas,concentration of the carrier medium and concentration of potassium borohydride,as well as the interferences of coexisting ions were studied and optimized.Linear relationship between values of fluorescence intensity and mass concentration of Hg was found in the range within 1.0 μg·L^-1,with detection limit（3s/k） of 0.8 ng·L^-1.Test for precision was performed with 0.5 μg·L^-1 Hg standard solution,the value of RSD（n=11） found was 0.95%.The proposed method was applied to the analysis of 2 calcium carbonate samples,and value of average recovery found by standard addition method was 103.5%.