镧─α─生物素与钙─α─生物素的稳定常数─稀土微量肥料低毒无害的研究

THE DETERMINATION OF THE STABLE CONSTANTS OF (Ⅲ) -α-BIOS AND Ca (Ⅲ)-α-BIOS

本文采用单核取代法［１］，在７２１分光光度计上分别测定了镧─α─生物素与钙─α─生物素络合物体系的光密度变化，从而解析出镧─α─生物素的稳定常数β１＝３．２９×１０４；β２＝１．６０×１０７。而钙─α─生物素的稳定常数β１＝５．１０×１０２；β２＝２．５８×１０６．可见前者比后者的稳定常数要大二个数量级，这说明稀土镧可与人体大量摄入的α─生物素络合，不会在人体中积累，也不可能竞争取代人体中的钙。从而在理论的一个方面证明稀土微肥是低毒无害的。

The changes of the photo-absorptivity of the complexion of La (Ⅲ) -α-Bios and Ca (Ⅱ) -α -Bios are determined by using 721 -spectrophotometer with thesingle nucleus replacement method.The stable constants of the two complexionsare obtained. The stable constants of La (Ⅲ)-α-Bios are β1=3. 29×104 andβ2=1. 60×107. For Ca (Ⅱ)-α-Bios, the former complexion's stable constants are as 102 as the latter's. The result proved that (1) the rare-earth element La (Ⅲ) taken in man's body may combined into a complexion with α-Bios ; (2) it does neither accumulate nor replace the element Ca (Ⅱ) in man's body; (3) therare-earth fertile is low toxic and unharmful to man.