悬浮液进样火焰原子吸收光谱法测定豆米类粮食中镁

FAAS DETERMINATION OF MAGNESIUM IN BEANS AND RICE USING THE SUSPENSION SAMPLING

将样品磨细配制成悬浮液 ,并对悬浮剂的选择及化学干扰的消除进行了考查。为消除化学干扰 ,取适量悬浮液 ,加入 La3+ 溶液制成试液。将试液喷入空气 -乙炔火焰 ,以空白溶液为参比 ,用工作曲线法进行测定。测定结果与灰化法一致 ,相对误差小于± 1 .3%。方法简便、快速。

It is proposed in this paper that the direct sampling in suspension solution is used instead of the conventional ashing method in the FAAS determination of Mg in beans and rice. The sample is ground into fine powder and made into a suspension solution. The suspension solution is then sprayed drectly into the air acetylene flame and its magnesium content is determined by the AAS method. Lanthanum(Ⅲ) solution is added to the suspension as a matrix modifier. The absorbance of the sample is read againt a blank treated in the same way as the sample and standard calibration curve is used in the determination. The results obtained by this method were checked with those obtained by the ashing method, and it is found that there is no significant divergence between the results of the two methods. The RSD found is smaller than ±1.3%. The method is proved to be simple, rapid and accurate.