一阶导数吸光光度法同时测定纯硅中铁和铝的研究

STUDY ON SIMULTANEOUS DETERMINATION OF ALUMINIUM AND IRON IN PURE SILICON BY FIRST DERIVATIVE SPECTROPHOTOMETRY

提出了用一阶导数吸光光度法同时测定铁和铝的方法。在pH 6.5乙二胺缓冲溶液中,乳化剂OP存在下,Fe^(3+)、Al^(3+)与络天青S形成Fe^(3+)、Al^(3+)-CAS-OP三元络合物,络合物一阶导数光谱等吸收点分别在606.2、638.0nm,记录混合体系在两波长处一阶导数值可以分别测定铝、铁含量,互不影响。铁、铝含量分别在1.0～16μg/25ml、0.3～10μg/25ml范围内呈良好线性,用于测定纯硅中铁、铝含量,结果满意。

A new method for Simultaneous determination of Fe and Al by first derivative spectrophotometry is reported in this paper. It can be seen from the first derivative absorption spectrum (Fig 2)that the complex Fe( Ⅲ )-CAS-OP has a positive absorption maximum at 606. 2nm and the complex Al( Ⅲ )-CAS-OP has a negative absorption maximum at 638. Onm . It is proposed that iron and aluminium can be determined at the aboved mentioned wavelength respectively where the co-existing component (eg, the presence of A13+ in the determination of Fe3+ and vise versa) showed a zero absorption. Thus,the interference between Fe3+ and A13+ is avoided,Beer' s Law is obeyed in the concentration range of 1. 0-16μg/25ml for iron and 0. 3-10μg/ 25ml for aluminium,The proposed method has been applied to the analysis of pure silicon with satisfactory results.