不同预处理方法对黑大豆中微量元素含量测定的影响

Impact on Determination of Trace Element Using Different Pretreatment Methods in Black Soybeans

采用湿法消解和微波消解2种前处理方法,用原子吸收光谱法快速测定黑大豆中Ca、Mg、Cu、Zn含量。结果表明:微波消解和湿法消解样品中Ca、Mg、Zn、Cu的含量分别为220.85、1834.03、27.09、8.77μg.g-1和221.08、1914.58、17.88、11.08μg.g-1,说明黑大豆中含有丰富的Ca、Mg元素,其次是Zn和Cu,样品的预处理方法不同,Ca、Cu、Zn的结果差别不大,Mg元素测定结果差别较大。微波和湿法消解后Ca、Cu、Zn加标回收率分别为83.76%、92.86%、96.54%和89.65%、87.50%、88.63%,各元素的精密度为0.2%～1.4%。Mg元素由于基体干扰,2种方法回收结果均不理想。综合考虑,微波消解预处理后元素的回收率较高,测定结果更为准确。

In the paper,the contents of Ca,Mg,Cu,Zn in black soybean were determined by atomic absorption spectrometry with wet and microwave assisted digestion,respectively.The results showed that,the Ca,Mg,Zn,Cu contents in the sample were 220.85,1834.03,27.09 and 8.77 μg·g-1,respectively,with microwave assisted digestion;when digested by wet method were 221.08,1914.58,17.88 and 11.08 μg·g-1,respectively.The black soybean contained rich inorganic trace elements of Ca,Mg.The concentration of Ca,Zn,Cu have little difference in the black soybeans sample with two pretreatment methods,but Mg elements varied greatly.The recovery of Ca,Cu and Zn using microwave digestion were 83.76%,92.86%,96.54%,respectively;the wet digestion were 89.65%,87.50%,88.63%,respectively.The precision of the four elements were 0.2%-1.4%.The recovery of Mg was not satisfactory using the two methods,it may be due to matrix interference.So the results of determination by the microwave pretreatment were more accurate than wet method.