氢化物发生-原子荧光光度法测定紫菜粉中总砷的几种前处理方法

Pretreatment methods for determination of total arsenic in seaweed powder by hydride generation atomic fluorescence spectrometry

目的通过测定经不同前处理方法处理的紫菜粉样品中的砷含量,比较各种前处理方法的消化效果,选择最优消化条件。方法紫菜粉分别用湿法消化（不同混酸）、干灰化法、微波消化后,采用氢化物发生-原子荧光光度法测定砷含量,通过对结果的比较,选择最佳消化方法。结果在灯电流为30mA,负高压为280V,载流为5%盐酸时,砷的浓度在0~80μg/L时线性关系良好,相关系数为0.999 9。不同的消化方法测定结果不同,湿法消解法相对于干灰化法、微波消解法更适用于紫菜粉中砷的测定,结果更接近真值。湿法消化的回收率为91.90%~101.30%,相对标准偏差为3.38%~4.01%。常见干扰元素锑、铅、镉、铜、锌对测定没有影响。结论湿法消化更适合氢化物发生-原子荧光光度法测定紫菜粉中的砷,采用8.00ml HNO3＋2.00ml HClO4＋0.60ml H2SO4的混酸比例,测定结果最理想。微波消解和干灰化法由于消解不完全导致测定结果偏低。

Objective To measure the content of arsenic in the samples of seaweed powder processed by different pretreatment methods,compare the digestion effect of various pretreatment methods,and select the optimal digestion conditions. Methods Seaweed powder samples were digested by wet digestion（different mixed acid）,dry ashing and microwave digestion,and hydride generation atomic fluorescence spectrometry was used to determine the arsenic content,through the comparison to choose the best digestion method. Results When the lamp current was 30 mA,the negative high voltage was 280 V,the current carrier of hydrochloric acid was 5%,the range of arsenic concentration was 0-80.00μg/L with good linear relation,the correlation coefficient was 0.999 9.Different digestion methods led to different results.The wet digestion method was more suitable than the other two methods,and the result was closer to the true value.The recovery of the method was 91.90%-101.30%,the relative standard deviation was 3.38%-4.01%.The common interfering elements such as Ti,Pb,Cd,Cu,and Zn had no effect on the results of determination. Conclusion Wet digestion is more suitable for hydride generation atomic fluorescence spectrometry in determination of arsenic in seaweed powder,using 8HNO3＋2.00 ml HClO4＋0.60 ml H2SO4 ml acid ratio,the result is the most ideal.Using microwave digestion and dry ashing digestion,the determination results are low due to incomplete digestion.