微波辅助提取原子吸收光谱法快速检测食品中铅、镉、锰、锌

Rapid detection of lead,cadmium,manganese,and zinc in food by microwave assisted extraction atomic absorption spectroscopy

采用微波辅助提取样品,建立食品中铅、镉、锰、锌的原子吸收光谱快速检测方法。以1%(体积分数)硝酸溶液为提取溶剂,在提取温度为120℃、提取时间为30min、样品质量为0.2~0.3g的条件下,食品中的铅、镉、锰、锌提取率均能达到81%~109%。铅的质量浓度在0~10μg/L范围内,镉的质量浓度在0~2.00μg/L范围内,锰、锌的质量浓度在0~1000μg/L范围内与吸光度具有良好的线性关系,相关系数均大于0.999。当取样质量为0.3g、定容体积为10 mL时,样品中铅、镉、锰、锌的检出限分别为0.006、0.001、0.2、0.05 mg/kg。在优化的实验条件下,标准物质GBW 10051中4种元素测定结果的相对标准偏差均小于10%(n=6),6种不同种类的国家标准物质的测定值与认定值基本一致,8种实际样品的测定结果与国标法测定结果的相对偏差为-19%~15%。该方法硝酸用量少,样品处理效率高,测量准确度高,适用于食品中铅、镉、锰、锌的快速检测。

An atomic absorption spectroscopy for the rapid detection of lead,cadmium,manganese,and zinc in food was established by using microwave assisted extraction.The extraction rates of lead,cadmium,manganese,and zinc in food were 81%-109%under the conditions of 1%(volume fraction)nitric acid solution as the extraction solvent,extraction temperature of 120℃,extraction time of 30 minutes,and sample mass of 0.2-0.3 g.The mass concentration had a good linear relationship with the absorbance in the range of 0-10μg/L for lead,0-2.00μg/L for cadmium,0-1000μg/L for manganese and zinc,the correlation coefficients were all more than 0.999.When the sampling mass was 0.3 g and the constant volume was 10 mL,the detection limits of lead,cadmium,manganese,and zinc in food samples were 0.006,0.001,0.2 and 0.05 mg/kg,respectively.Under the optimized experimental conditions,the relative standard deviation of the determination results of four elements in the standard substance GBW 10051 was all less than 10%(n=6).The determination results of six different types of national reference materials were basically consistent with the confirmed values.The relative deviations between the determination results of eight actual samples and the results of that by the national standard method were-19%-15%.The method has less nitric acid consumption,high sample processing efficiency,and high measurement accuracy,which is suitable for the rapid detection of lead,cadmium,manganese,and zinc in food.