盐酸恩诺沙星平衡水溶解度的测定

利用水平摇床充分溶解盐酸恩诺沙星，在10h以内得到pH5．3的稳定的饱和溶液，用紫外分光光度计测定室温下盐酸恩诺沙星的平衡水溶解度，研究pH对盐酸恩诺沙星溶解度的影响，为测定盐酸恩诺沙星溶解度提供一种简单易行、科学准确的检测方法，为其生态风险评价及相关研究提供数据。结果表明，当盐酸恩诺沙星饱和水溶液pH分别为2．8、4．0、5．3、7．0、8．2和9．9时，室温下溶解度分别为1．161g／L、10．637g／L、19．770g／L、4．198g／L、1．874g／L和16．108g／L；盐酸恩诺沙星水溶液在pH5．3时溶解度最大，溶液中的恩诺沙星绝大部分以阳离子形式存在，小部分以两性离子形式存在；溶解度次最大时PH为9．9，此时的恩诺沙星几乎完全以阴离子形式存在于溶液中。

Detection of Solubility of Enrofloxacin Hydrochloride

The aim of this study is to provide a feasible, effective and scientific detection method, and experimental data for basic related research. Equilibrium water solubility of enrofloxacin hydrochloride was measured by UV-Vis spectrophotometer at room temperature, and the influence of pH value in the solution on the solubility was studied. The solubility was 1. 161g/L, 10.637 g/ L, 19. 770g/ L, 4. 198g/ L, 1.874 g/ Land 16. 108 g/ Lat pH value of 2.8, 4.0, 5.3, 7.0, 8.2 and 9.9, respectively. The major species of enrofloxacin was cationic form, and a very small proportion of zwitterionic form presented when pH value of enrofloxacin hydrochloride solution was 5. 3. The submaximal solubility occurred at pH of 9.9, and anion form was the dominant species in the solution.