食品添加剂碳酸钙中铅含量测定方法的研究

Study on method for determination of lead in food additive-Calcium carbonate

食品级碳酸钙已被广泛应用于现代生活食品和医药行业,在食品生产过程中,添加碳酸钙的同时,其中所含的有害元素铅会对产品产生污染,因此,有必要对该类元素进行检验并有效监控。采用氢化物发生-原子吸收光谱法(HG-AAS)测定食品添加剂碳酸钙中铅含量,并对实验条件、测定的干扰情况及样品的前处理方式进行了讨论。在该方法条件下,样品中铅通过生成气态氢化物与基体分离并得到富集,消除了基体组分的干扰,提高了测定结果的准确度和灵敏度。通过实验比较,选择0.1%0.3%(v/v)盐酸溶液作为控制体系的适宜酸度。方法的特征浓度为0.32μg/L,检出限为0.12μg/L,样品测定的相对标准偏差为1.39%3.40%(n=11),加标回收率为94.8%104.3%。

The food grade calcium carbonate has been widely used in foodstuffs and medicine in modern life. In food producing process,as calcium carbonate was added into foods,the harmful lead contained in calcium carbonate would pollute the product at the same time. Therefore,it is necessary to determine and effectively monitor this kind of element. A method of hydride generation-atomic absorption spectrometry (HG-AAS)was applied to determination of trace amounts of lead in food additive -Calcium carbonate. And experimental conditions,the interference of measurement and the pre-treatment of samples methods were discussed. Under the optimum conditions,the lead in the sample was enriched through separation from substrate by producing of gaseous state hydride. And the substrate component interference was eliminated.So the method enhanced the accuracy and the sensitivity of determination.By comparison,0.1%0.3%(v/v) hydrochloric acid solution was selected to control suitable acidity of system.The proposed method was used to determine food samples with characteristic concentration of 0.32μg/L and the detection limit of 0.12μg/L,and values of the relative standard deviation were in range of 1.39% to 3.40%(n=11),and the recovery of added samples was in range of 94.8% to 104.3%.