在硝酸酸度约为1.3 mol·L-1硼酸试样溶液中加入硝酸银溶液,使溶液中存在的微量氯离子与之反应生成氯化银胶悬体,加入适量的1,2,3-丙三醇作为胶悬体的稳定剂.选择在400 nm波长处测定此胶悬体的吸光度,其吸光度与氯离子浓度在0.017~0.20 mg·L-1范围呈线性关系,求测方法的检出限(3S/b)为0.016 mg·L-1.对此反应的各影响因素(如检测波长、试液酸度、硝酸银溶液及丙三醇的加入量、反应的适宜温度时间,以及进行吸光度测定的时间等)作了较系统的试验并予以优化.对方法的回收率及精密度也作了试验,所得回收率在96.0%~102.6%之间,测得的相对标准偏差(n=5)均小于2%.

In a nitric acid medium of ca.1.3 mol·L-1,chloride ion in sample solution of boric acid was reacted with silver nitrate to form a colloidal suspension of silver chloride,which was stabilized by adding an appropriate amount of 1,2,3-propantriol (also named popularly as glycerol).Absorbance of the colloidal suspension was measured at the wavelength of 400 nm.Linear relationship between values of absorbance and concentration of Cl--ion was obtained in the range of 0.017- 0.20 mg·L-1.Detection limit (3S/b) of the method was found to be 0.016 mg·L-1.Variou influential factors of the reaction (including wavelength of measurement,acidity of test solution,amounts of silver nitrate solution and 1,2,3 propanetriol required,temperature and time suitable for the reaction,and time at which to make the measurements) were studied and optimized.Recovery and precision were tested,giving values of recovery in the range of 96.0%-102.6%,and values of RSD′s (n=5) less than 2%.