季铵盐结构与高氯酸根离子选择电极性能关系的研究

本文报道了由七种长链季铵盐制得的高氯酸根离子选择电极,测定了这些电极的Nernst响应范围和检测下限,并研究了各种阴离子的干扰。通过大量实验测得,随着季铵盐分子中取代烷基碳链的增长,电极电势响应范围增宽、检测下限降低、抗外部阴离子干扰能力增强。若取代烷基碳链过长,则季铵盐纯化困难,在膜相中溶解度降低,不适于电极的研制。根据用上述七种选择电极在相同水相条件下测得的数据表明,阴离子的干扰次序为:PA~->ClO_4~->BF_4~->SCN~->I~->ClO_3~->N_3~->N_3~->CN~-～Br~->H_2PO_4~->F~->Cl~-。这些数据对阴离子选择电极研制与相转移催化反应研究均有现实意义。

A study of the relationship between the chemical structure of quarternary ammonium salts and the functions of perchlorate ion selective electrodes.

For the preparation of perchlorate ion selective electrode (ISE), seven quarternary ammonium salts with different carbon chain lengths were used as the active phase component of ISE. The Nernst response ranges and the detection limits of those electrodes were measured and the effect of interfering anions was discussed in detail. It was noticed that the functions of ISE were closely related to the chemical structure of quarternary ammonium salts, the linear response of the electrode potential increased with the increase of the carbon chain length of the alkyl group in the quarternary ammonium salts, but with decrease in the detection limit. The interference of foreign anions could be reduced to some extent, when the electro-active components with longer carbon chains were used. However the aliphatic quarternary ammonium salts with very long carbon chains are not recommended to be the suitable active materials of ISE due to the difficulties in their purification and the low solubility of them in PVC matrix. The order of exchange reactivity of anions in terms of selective coefficients measured by mixed solution methods is as follows: picrate anion > ClO4*- > BF4*- > SCN*- > I*- > ClO3*- > NO3*- > N3*- > CN*- -Br*- > H2PO4*- > F*- > CL*-. The results mentioned above will be useful in some applications, such as in the preparation of ISE and in the study on phase transfer catalysis.