腺苷钴胺水溶液的光降解动力学研究

目的：考察腺苷钴胺水溶液的光降解动力学特征。方法：运用HPLC法测定水溶液中腺苷钴胺含量及有关物质。考察样品浓度、光强度、温度、pH对腺苷钴胺水溶液光稳定性的影响。结果：经线性拟合对比分析，腺苷钴胺溶液的光降解反应级数为n=1，腺苷钴胺溶液对光极敏感，在pH2．5—3．5的溶液中相对稳定，腺苷钴胺溶液的光降解随样品浓度的降低、光强度的升高而增加，恒温避光加速试验中腺苷钴胺溶液的光降解并不随温度的升高而升高，但恒温光照加速试验中温度的升高明显加速腺苷钴胺溶液的光降解。结论：腺苷钴胺溶液光降解属近似一级动力学过程，光降解速率受溶液pH影响显著，热可加速腺苷钴胺溶液的光降解。

Study on Photodegradation Kinetics of Cobamamide Aqueous Solution

Objective： To investigate the photodegradation kinetic characteristics of cobamamide aqueous solution. Method： An HPLC method was used for the content determination of cobamamide and its correlated substance in the aqueous solution. The photodeg- radation stability of cobamamide aqueous solution under various light illuminance, various temperature and various pH solutions were studied. Result： With comparative regression analysis of linear fit, the photodegradation kinetic order of cobamamide aqueous solution was determined as n = 1. The cobamanfide aqueous solution was most unstable under light and was relatively stable at pH 2. 5-3.5. The lower the concentration of sample and the higher the illuminance of light, the photodegradation kinetic rate constant was higher. There was not increased the photodegradation kinetic rate constant , as the temperature increased in isothermal accelerated experiments proceeded in the dark, but the photodegradation kinetic rate constant was increased, as the temperature increased in isothermal accelerated ex- periments exposed to light. Conclusion： The photodegradation of cobamamide aqueous solution follows apparent first-order kinetics. The photodegradation kinetic rate is affected by pH remarkably and heat can accelerate the photodegradation kinetic rate of cobamamide aqueous solution.