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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 determine the arsenic content of seaweed samples treated with different pretreatment methods and compare the digestion effects of various pretreatment methods to select the optimal digestion conditions. Methods Porphyra yezoensis was digested by wet method (different mixed acid), dry ashing method. After microwave digestion, the content of arsenic was determined by hydride generation - atomic fluorescence spectrophotometry. The best digestion method was selected by comparing the results. Results When the lamp current was 30mA, the negative voltage was 280V, and the current was 5% hydrochloric acid, the linearity of arsenic was between 0 ~ 80μg / L with a correlation coefficient of 0.999 9. The results of different digestion methods are different. Compared with the dry ashing method, the microwave digestion method is more suitable for the determination of arsenic in seaweed powder, and the result is closer to the true value. The recovery rate of wet digestion was 91.90% ~ 101.30% with relative standard deviation of 3.38% ~ 4.01%. Common interference elements Antimony, lead, cadmium, copper, zinc has no effect on the determination. Conclusions Wet digestion is more suitable for the determination of arsenic in seaweed by hydride generation - atomic fluorescence spectrometry. The optimal ratio is 8.00ml HNO3 + 2.00ml HClO4 + 0.60ml H2SO4. Microwave digestion and dry ashing due to incomplete digestion lead to lower measurement results.