论文部分内容阅读
有关钙离子选择电极的应用研究已有报道,但以直接电位法居多,方法虽简便,但对于二价离子而言,当电位测量误差为1毫伏时,就会产生相当于8%的浓度误差。因此,应用直接电位法测定高含量的钙时,很难满足测定准确度和精密度的要求。但如应用钙离子电极为指示电极,以电位滴定法测定钙,则可减少误差影响因素,提高测定的准确度和精密度。本文借助于钙离子电极为指示电极,用三乙醇胺掩蔽Fe、Al、Ti,利用EGTA对钙离子有高的选择性,消除常规测钙方法中由于Mg(OH)_2对钙的沉淀吸附而造成的测定误差,以望能在一定量镁的共存下准确测定钙。实验证明,结果令人满意。
The application of calcium ion selective electrode has been reported. However, the direct potential method is mostly used. Although the method is simple, for bivalent ions, when the potential measurement error is 1 mV, a concentration equivalent to 8% error. Therefore, the application of direct potential method for the determination of high levels of calcium, it is difficult to meet the measurement accuracy and precision requirements. However, if the application of calcium ion electrode as the indicator electrode, potentiometric titration of calcium, you can reduce the error factors to improve the accuracy and precision of the determination. In this paper, with the help of calcium ion electrode as the indicator electrode, triethanolamine masked Fe, Al, Ti, the use of EGTA has a high selectivity for calcium ions, eliminating the conventional calcium measurement method due to the precipitation of Mg (OH) _2 on calcium precipitation caused The determination of error in the hope that a certain amount of magnesium in the presence of accurate determination of calcium. Experiments show that the results are satisfactory.