分光光度法测定豆类中的锌含量

Determination of Zinc in beans by spectrophotometry

采用双硫腙分光光度法测定了四种豆类中的锌含量.豆类样品经粉碎机打碎,成粉末状,再经马弗炉灰化处理后,用吸收液吸收灰化产物,得到样品液.在波长为525nm条件下,采用分光光度法测其吸光度,根据标准曲线回归方程A=0.675C＋0.146（r=0.999 8）,由样品的吸光度可求出样品液中锌的含量.结果表明,在所测豆类中绿豆中的锌含量最高,黑豆中的锌含量最低,加标回收率为98.19%～101.08%,RSD在0.55%～2.15%之间,适合用来测定食品中的微量元素锌含量.

The content of zinc in four kinds of beans was determined by dithizone spectrophotometry.First, four kinds of beans were crushed into power,the ashing products were absorbed by the acid solution to obtain the sample solution.Under the condition of 525 nm,the absorbance was determined by spectrophotometry,according to the standard curve regression e- quation A = 0.675C ＋0.146 （ r = 0.999 8）, the content of zinc in sample solution was calculated by the absorbance, the average spike recovery was 98.19%-101.08%,RSD was 0.55%-2.15%.The results showed that the content of zinc in Mung bean was the highest, the content of zinc in Black bean was the lowest, suitable for the determination of trace zinc in food.