火焰原子吸收光谱法测定粗锌中的镉

Determination of cadmium in crude zinc by flame atomic absorption spectrometry

建立了测定粗锌中镉的火焰原子吸收光谱法。粗锌样品经硝酸溶液(1+1)溶解,以体积分数约为5%的硝酸溶液为测定介质,使用空气–乙炔火焰,以水调零,选定228.8 nm为测定波长。干扰试验表明,锌的基体和其它杂质元素均不干扰镉的测定。在选定的仪器条件下,镉在0.20~3.00μg/mL范围内与其对应的吸光度呈良好的线性关系,相关系数为0.999 6,方法检出限为0.02μg/mL。镉的加标回收率为98%~101%,测定结果的相对标准偏差为0.70%~2.70%(n=7)。该法准确可靠,灵敏度高,干扰少,重现性好,适用于镉含量在0.001 0%~2.00%之间的粗锌中镉的测定。

The flame atomic absorption spectrometry （AAS） method was established for determination of cadmium incrude zinc samples. The crude zinc samples was dissolved by nitric acid solution （1＋1）,using nitrate solution whose volumefraction was about 5% and air acetylene flame,with water adjusted to zero,with 228.8 nm as the detection wavelength.The interference test showed that the zinc matrix and other impurity elements did not interfere with the determination ofcadmium. Under the selected conditions of the instrument,the mass concentration of Cd and its absorbance showed a goodlinear relationship in the range of 0.20–3.00 μg/mL with the correlation coefficient of 0.999 6,and the detection limitwas 0.02 μg/mL. The recovery rate was 98% – 101%,and the relative standard deviation of determination results was0.70%–2.70%（n=7）. The method has the advantages of high accuracy,reliability,and sensitivity,low interference and goodreproducibility,and it is suitable for determination of the cadmium in crude zinc with cadmium content of 0.001 0%–2%.