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一、前言曾经証明,在氨羧络合滴定中,当干扰离子N与被测离子M同时存在时,如果pK′_(MY)愈大,pK′_(NY)愈小;原始浓度M_0愈大,N_0愈小,则滴定M离子的誤差愈小。因此,适当提高溶液的酸度(利用酸效应)以降低干扰离子的pK′_(NY)值,或加入其他络合剂(利用络合掩蔽效应)以降低干扰离子浓度N_0,都可得到消除干扰的效果。当干扰离子与某种试剂生成难溶的沉淀时,也能降低干扰离子浓度,达到掩蔽干扰的目的,称为沉淀掩蔽效应。在络合反应与沉淀反应之间的平衡情况,文献,曾用数学推导作过某些说明,但对络合滴定中
I. Preface It has been proved that when the interference ion N is present at the same time as the measured ion M, the smaller the pK ’_ (NY) is, if the pK’ _ (MY) Large, N_0 smaller, the smaller the error of titration M ions. Therefore, it is possible to eliminate the interference by properly increasing the acidity of the solution (using acid effect) to reduce the pK ’_ (NY) value of the interfering ions or adding other complexing agents (using the complexing masking effect) to reduce the interference ion concentration N_0 Effect. When interfering ions and a certain agent to generate insoluble precipitate, but also reduce the concentration of interfering ions to achieve the purpose of masking interference, known as the precipitation masking effect. In the complexation reaction and precipitation between the balance of the situation, the literature, has made some explanations using mathematical deduction, but the complexation titration