光度法研究姜黄素与铁(Ⅲ)的络合反应

Spectrophotometric study of curcumin's complex reaction with iron(Ⅲ)

目的研究姜黄素与铁(Ⅲ)的络合反应,并建立铁的测定方法。方法采用分光光度法。结果在10^(-5)～10^(-3)mol/L范围内,姜黄素有不同的吸收光谱;其与铁络合物的吸收波长由430nm红移至496 nm,呈增色反应。在pH 5.60,浓度为6.51×10^(-4)moL/L姜黄素液中,络合物为酒红色,λ_(max)=496 nm,ε=3.86×10~6L/mol·cm,铁(Ⅲ)的线性范围为0.20～2.00μg/mL。结论在较高浓度下自动聚合的姜黄素与铁(Ⅲ)反应更灵敏。在此基础上,建立的姜黄素测定铁的分光光度法操作简单,选择性较好,灵敏度高,用于自来水中铁(Ⅲ)的测定,结果满意。

Aim To study the curcumin＇s complex reaction with Fe （Ⅲ） and develop a spectrophotometric method of determination of Iron （Ⅲ）. Methods Spectrophotometry was used. Results In the range of 10^ -5 - 10^-3 mol/ L, curcumin had different absorption spectrograms. The absorption wavelength of the curcumin-Fe （Ⅲ） complex was red shift from 430 nm to 496 nm and its absorbance increased. In the pH 5.6 solution containing 6. 51 ^ 10 ^-4 mol/L curcumin, the complex is claret-red and the molar absorptivity is 3.86 × 10^4 L/mol · cm at λmax = 496 rim. The calibration curve is linear in the range 0. 20 - 2. 00 μg/mL for Fe （Ⅲ）. Conclusion At the higher concentration, polymerized curcumin is more sensitive to react with Fe （Ⅲ）. Based on this, a simple, selective and sensitive spectrophotometric method has been developed and applied satisfactorily to determine Fe（ Ⅲ） in tap water.