Analysis of lead concentrations of foods in some supermarkets in Beijing

Objective:To analyze concentrations of lead in foods sold in some supermarkets in Beijing and to provide reference for local food safety assessment. Methods:496 food samples of 28 types were collected from nearly 40 supermarkets. Concentrations of lead was determined by using graphite furnace atomic absorption spectrometry(GF-AAS),the detection limit was 0.005 mg·kg^-1,and linear correlation coefficient was between 0.9989~0.9995 when mass concentration stay within 0~20 μg·L^-1. Results:The average concentration of lead of those samples was 0.0957 mg·kg^-1,and 95% confidence interval was 0.0191~0.2104 mg·kg^-1. Conclusion:Hierarchical cluster analysis showed that concentrations of lead decreased in the following order:spices and liquid seasoning(class Ⅰ),semisolid condiments and instant noodles(class Ⅱ),and other 24 kinds of samples including wheat flour,white wine and vegetables(class Ⅲ). Lead concentrations of the above three classes were 0~2.8944,0~0.3328,0~0.0983 mg·kg^-1,respectively.