用分光光度法确定碘和淀粉显色反应的定量测定条件

Determining condition of chromogenic reaction between iodine and amylum quantitatively by means of spectrophotometer

为了确定碘和淀粉反应的定量关系,本文利用分光光度计定量地研究了碘和淀粉显色反应过程中吸光度的变化规律,发现碘和淀粉显色反应的最大吸收波长为610 nm,碘和淀粉显色反应的吸光度在七小时内基本不变,可以进行比色分析。对于淀粉标准系列溶液,随着显色剂碘标准溶液剂量的增加,吸光度在增大,当I2取8 ml时,定量测定淀粉的标准曲线线性关系最好。对于碘标准系列溶液,随着显色剂淀粉用量的增加,溶液的颜色加深,吸光度在增大,标准曲线的线性部分加长,加入淀粉为20 ml和50 ml时,直线部分的长度变化不大,因此,加入20 ml最为理想。

To determine the condition of chromogenic reaction between iodine and amylum quantitatively,the author studied the law in the course of chromogenic reaction between iodine and amylum with the aid of spectrophotometer quantitatively,and found that maximum absorption wavelength is 610 nm,and the absorbance in the course of chromogenic reaction between iodine and amylum has not changed within 7 hours.The absorbance increases as the increase of the quantity of standard solution iodine.While the volume of standard solution iodine is 8 ml,the relationship between absorbance and amylum quantity possesses linearity well.With the increase of amylum quantity,the color of each the standard solution iodine combined with amylum changes dark and the its absorbance enlarges,the linear part in standard curve enlarges,while the amylum quantity are 20 ml and 50 ml respectively,the length of linear part in standard curve is not changed,so the optimum quantity of amylum is 20 ml.