辽宁地区主要粮食中铅、镉含量的分析

摘要

原子吸收光谱法对辽宁地区主要粮食中铅、镉含量进行测定及相关分析。样品干燥、研磨过200目筛，每份称取5.0000 g于250 mL锥形瓶中，加入HNO3：HClO4为3：1混酸10 mL浸泡过夜，加几颗玻璃珠，置于电热板上缓慢加热消化，直至冒白烟。当消化液剩约3~5 mL时，冷却，移入25.00 mL容量瓶中，二次蒸馏水定容，备用。原子吸收法测定。铅在0.00~15.00μg·mL-¹范围内具有线性关系，r=0.9998，测定铅的RSD(n=5)=3.65%，标准加入法测定铅的回收率为88.7%；镉在0.00~5.00μg·mL-¹范围内具有线性关系，r=0.9791，测定镉的RSD(n=5)=4.27%，标准加入法测定镉的回收率为93.2%。测定方法快速简便，结果准确。辽宁工业发达地区的粮食样品中铅、镉含量显著高于其它样品。%The contents of lead and cadmium in main foodstuffs from Liaoning Provence were determined.The sample was dried and grinded. 5.000 g Sample was put in 250 mL conical flask, and then 10 mL mixed acid of HNO3 and HClO4(3:1) was added into the conical flask to immerse the sample more than 24 h. Sample digestion was slowly done on the electric heater until a little of white smoke rose from conical flask. The sample digestion solution was transferred into 25 mL volumetric flask when the sample digestion solution in conical flask was about 3~5 mL. Sample digestion solution was filtrated, and then determined by AAS directly. The linear relationship of lead in the range of 0.00~15.000μg·mL-1 is good (r=0.9998). RSD (n=5) is below 3.65%. The recovery of lead is 88.7%; The linear relationship of cadmium in the range of 0.00~5.00μg·mL-1 is good (r=0.9791). RSD (n=5) is below 4.27%. The recovery of cadmium is 93.2%.The determination method is simple and the determined results are accurate. The contents of lead and cadmium in main foodstuffs samples from industrial developed area of Liaoning Provence are more than the others.