不同消解体系对原子荧光法测定汞含量的影响

Effect of Different Digestion System on Mercury Determination by Atomic Fluorescence Spectormetry

[目的]探究湿法消解中不同消解体系前处理对原子荧光法测定食品中汞含量的影响,并找出适宜的前处理消解体系。[方法]采用湿法消解-氢化物原子荧光光谱法,通过改变方法前处理中消解体系混合液配比的处理,对3个样品(大米、海带、香菇)的汞含量进行测定,并综合分析不同消解体系处理对原子荧光光谱法测定汞的影响。[结果]选择仪器适宜工作条件,汞的检出限为0.004μg/L; 11次空白溶液相对标准偏差(n=11)为2.53%,线性范围为0～1μg/L;回归方程得出相关系数r=0.999 0,回收率为95.4%～99.5%。分析得出不同消解体系处理对汞测定的影响主要为混酸的氧化强度影响消解效果和消解体系温度高致使汞元素挥发散失。[结论]以硝酸-过氧化氢-高氯酸为消解体系时消化效果最佳,该方法消解的样品消解完全,用时短,耗能低,试剂用量少,原子荧光法检测结果准确,推荐使用。

[Objective] The research aimed to study the effect of different digestion system pretreatment on determination of mercury in food by atomic fluorescence spectrometry to find a suitable pre-treatment digestion system. [Method] Wet digestion-hydride atomic fluorescence spectrometry was used to determine the Hg content of three samples（rice, kelp, shiitake）by changing the ratio of the mixed solution in the pretreatment of the method, and the effects of different digestion systems on the determination of mercury by atomic fluorescence spectrometry were analyzed.[Result]The results showed that, while the instrument was suitable for working conditions ,the detection limit of mercury was 0.004 μg/L , the relative standard deviation （ n = 11）was 2.53% and the linear range was 0-1 μg/L.The regression equation obtained correlation coefficient r = 0.999,the recovery rate was 95.4%-99.5%. It is concluded that the effect of different digestion systems on the determination of mercury is mainly due to the effect of the oxidation intensity of the mixed acid on the digestion and the high temperature of the digestion system, resulting in the loss of mercury.[Conclusion]The digestion was best when the nitric acid-hydrogen peroxide-perchloric acid was used as the digestion system. Under this method, the sample was digested completely with a short time,low energy consumption,less reagent dosageand and the test results were accurate, the method was recommended use.