微波消解-石墨炉原子吸收光谱法测定食用菌中总砷

Determination of Total Arsenic in Edible Mushrooms by Furnace Atomic Absorption Spectrometry with Microwave Digestion

采用微波消解-石墨炉原子吸收光谱法测定食用菌中总砷。取可食部分的食用菌粉碎均匀,采用微波消解对样品进行消解,将消解液于140℃赶酸至0.5 mL,用超纯水转移定容至25 mL。以硝酸钯(1 g/L)为基体改进剂,塞曼扣背景,用石墨炉原子吸收光谱法测定总砷。检出限为0.4μg/L,线性范围为0~30μg/L,线性相关系数(r)大于0.998,采用精密度考察方法重现性,不同浓度水平的相对标准偏差(RSD)均小于6.6%;三个浓度水平的加标回收率为80.6%~104%,有证标准物质测定结果符合要求。实验结果表明,方法操作简便、灵敏、准确,适合食用菌中总砷的测定。对砷形态复杂的野生食用菌,微波消解后可直接采用石墨炉原子吸收光谱法测定总砷。

The total arsenic in edible mushrooms was determined by microwave digestion-graphite furnace atomic absorption spectrometry.The edible part of the edible mushrooms was crushed evenly,followed by microwave digestion.After complete digestion,the acid was concentrated at 0.5 mL with 140℃,and the volume was fixed to 25 mL with ultrapure water.Total arsenic was determined by graphite furnace atomic absorption spectrometry with palladium nitrate(1 g/L)as matrix modifier and Zeeman background correction.The limit of the detection was 0.4μg/L,the linear range of detection was 0—30μg/L,and the linear correlation coefficient(r)was greater than 0.998.The reproducibility of the method was determined by precision,and the(RSD)of different concentration levels was less than 6.6%.The recoveries at three spiked levels ranged from 80.6%to 104%.It is proved that the determination results of the certified reference material meet the requirements.This study showed this method was simple,sensitive and accurate for the determination of total arsenic in edible mushrooms.For edible wild mushrooms with complex arsenic species,the total arsenic can be determined directly by graphite furnace atomic absorption spectrometry after microwave digestion.