基于改进钛铁分光光度法测定柠檬酸液中的三价铁

Determination of ferric ions content of citric acid based on improved tiron spectrophotometry

基于改进钛铁分光光度法,通过pH理论计算确定缓冲溶液配比,建立了高浓度柠檬酸液中三价铁离子的测定方法。研究表明,柠檬酸浓度与所对应的缓冲溶液配比呈二次曲线关系,相关系数达到1;测定高浓度柠檬酸液中三价铁的较佳波长为480 nm,三价铁在1～10 mg/L呈良好的线性关系(r=0.999 6),加标回收率为95.5%～100.5%,重现性好。

The method of ferric ions content in high concentration citric acid based oll the improved tiron spectrophotometry was established. And the buffer solution ration was determiffated by theoretical calcula- tion of pH. Results indicated that the relation between ratio of buffer solution and the concentration of cit- ric acid was quadratic function, the correlation coefficient was 1. The optimal absorption wavelength of fer- ric ion in higher concentration of citric acid based on the improved tiron spectrophotometry was 480 rim. There was a good linear relationship between absorbance and content of ferric ion in range of 1-10 rag/L, and the correlation coefficient was 0.999 6. The recovery of standard addition was 95.5%-100.5%, good reproducibility.