pH值对尿酸溶解度影响的实验研究

Study on the effect of pH value on the solubility of uric acid

目的:探讨室温下(20~22℃)pH值对尿酸(uric Acid,UA)溶解度的影响,为深入了解体内UA的溶解与析出提供理论依据。方法:分别将UA溶于NaOH溶液和PBS溶液中制备母液,然后将母液配置成不同浓度和pH值的UA溶液;相同pH值下的UA溶液,取最低浓度1 000μmol/L为标准UA溶液,经紫外分光光度计检测其吸光度值,每个样本检测3次,取均值建立标准曲线方程。分别于0 h和24 h,检测其它不同浓度和pH值的样本溶液,重复3次。结果:(1)在NaOH溶液中,分别在0 h和24 h时对1 000、2 000、3 000和4 000μmol/L样本溶液中UA的溶解度进行检测,结果显示随pH值的升高UA的溶解度也不断升高;但5 000和6 000μmol/L样本溶液中,在0 h时UA的溶解度随pH值的升高而升高,在24 h时UA的溶解度随pH值的升高呈现先升高后降低的趋势,当pH值为7.0时UA的溶解度最高,且测得浓度与理论浓度基本一致。(2)在PBS溶液中,0 h时对1 000、2 000、3 000、4 000、5 000和6 000μmol/L样本溶液中UA的溶解度进行检测,结果显示随pH值的升高UA的溶解度不断升高,当pH值为7.0及以上时,UA的溶解最高,且测得浓度与理论浓度基本一致;在24 h时对上述溶液进行重复检测,结果显示在pH值为8.0时,各样本溶液UA溶解度的测得浓度与理论浓度基本一致,当pH值降低时,UA的溶解度不断降低。在1 000、2 000和3 000μmol/L样本溶液中,当pH值为6.0和7.5时,UA的溶解度均出现大幅度下降的现象。在NaOH和PBS溶液中,除1 000μmol/L样本溶液外,其它样本溶液均出现不同程度的晶体析出,经过红外光谱测定晶体为UA。结论:pH值可以显著影响UA的溶解与析出。

Objective:To investigate the effect of pH value on uric acid(UA)solubility at room temperature(20~22℃),and to provide a theoretical basis for further understanding the dissolution and precipitation of UA in vivo.Methods:UA was dissolved in NaOH solution and PBS solution respectively to prepare mother solution,and then the mother solution was prepared into UA solution with different concentration and pH.The UA solution at the same pH value was taken as the standard UA solution with the lowest concentration of 1 000μmol/L.The absorbance value was measured by an ultraviolet spectrophotometer,and each sample was detected 3 times,and the standard curve equation was established by taking the mean value.Other sample solutions with different concentrations and pH values were tested at 0 h and 24 h,respectively,and repeated 3 times.Results:(1)In NaOH solution,the solubility of UA in 1 000,2 000,3 000 and 4 000μmol/L sample solutions was detected at 0 h and 24 h,respectively.The results shown that the solubility of UA increased with the increase of pH.However,in the sample solutions of 5 000 and 6 000μmol/L,the solubility of UA increased with the increase of pH at 0 h,and increased first and then decreased with the increase of pH at 24 h.When the value was 7.0,the solubility of UA was the highest,and the measured concentration was basically consistent with the theoretical concentration.(2)In PBS solution,the solubility of UA in sample solutions of 1 000,2 000,3 000,4 000,5 000 and 6 000μmol/L was detected at 0 h.The results shown that the solubility of UA increased with the increase of pH value.When the pH value was 7.0 or above,the measured concentration of UA was basically consistent with the theoretical concentration.While testing the above solution at 24 h,the results shown that each of the sample solution UA solubility in the pH value of 8.0,measured concentrations are consistent with the basic theory of concentration.With the decrease of pH value,the solubility of UA decreased continuously.In 1 000,2 000 and 3 000μmol/L in the sample solutions,when the pH value of 6.0 and 7.5,the phenomenon of the solubility of UA all decreased significantly.In NaOH and PBS solutions,crystal precipitation occurred in all sample solutions except 1 000μmol/L sample solution,and the crystal was determined as UA by infrared spectroscopy.Conclusion:The pH value can significantly affect the dissolution and precipitation of UA.