铁强化酱油中NaFeEDTA含量的测定

Study on Analysis Method of NaFeEDTA in Iron Fortified Soy Sauce

在酸性(pH≤1.35)条件下,螯合物NaFeEDTA中的铁完全解离成游离的Fe3+与显色剂硫氰酸铵发生反应生成红色络合物,此红色络合物在483.0nm波长处有最大吸收峰,且吸光度与浓度呈线性关系。利用此线性关系可以精确测定出铁强化酱油中NaFeEDTA的含量。此方法的线性范围在2.028～24.336μg/ml(以NaFeEDTA含量计)之间,线性相关系数为0.99992。该方法简单、快速、灵敏,是测定铁强化酱油中NaFeEDTA含量的有效方法。

NaFeEDTA as a five-cycle chelating compound can be totally disassembled to produced Fe3＋under acid condition （pH≤ 1.35）. Fe3＋ can react with ammonium thiocyanate and forms red color complex. This red color complex has special absorption at 483 nm and the absorption is linear with the concentration of the complex. To take advantage of this principle, the content of NaFeEDTA in fortified soy sauce could be accurately measured. The results showed that the absorption has good linear relationship with the concentration of NaFeEDTA between 2.028 -24.336μ g/ml and the correlation coefficient is 0.99992, The method is a simple quick and accurate approach for the determination of the content of NaFeEDTA in iron fortified soy sauce.