一种利用分光光度法测定多酚化合物与金属离子络合反应化学计量比的方法

（1）分别配置等摩尔浓度的多酚溶液和金属离子溶液及反应缓冲液；（2）分别向1 mL比色皿中加入0-20 μL金属离子溶液及20-0 μL多酚溶液，使得每次加入的金属离子溶液和多酚溶液总体积保持为20 μL不变，然后补加反应缓冲液至1 mL，充分混合，放置1-2 min；（3）每次混合后，用分光光度计测定反应溶液在330 nm下的吸光度值；（4）收集每次测定的吸光度值，利用MatLab软件进行四项式曲线模拟，得到曲线最高点对应的X值，即为络合物的化学计量比。本发明技术操作简单、便捷、对仪器设备要求低、稳定性好。

(1) Separately prepare polyphenol solutions, metal ion solutions, and reaction buffer solution, where the polyphenol and metal ion solutions are at equal molar concentrations;
(2) Add 0-20 μL of metal ion solution and 20-0 μL of polyphenol solution to each 1 mL cuvette, ensuring that the total volume of the two added solutions remains exactly 20 μL for each preparation. Then top up with reaction buffer solution to a final volume of 1 mL, mix thoroughly, and allow standing for 1 to 2 minutes;
(3) Following each mixing step, measure the absorbance of the reaction solution at 330 nm using a spectrophotometer;
(4) Collect all absorbance values obtained from the measurements, and perform quartic polynomial curve fitting using MATLAB software. The X-value corresponding to the peak of the fitted curve represents the stoichiometric ratio of the coordination complex.
This technology features simple and convenient operation, low instrumentation requirements, and excellent stability.