Determination of surface pKa of SAM using an electrochemical titration method

被引：1

作者：

Zhao, JW ^{[1
]}

Luo, LQ ^{[1
]}

Yang, XR ^{[1
]}

Wang, EK ^{[1
]}

Dong, SJ ^{[1
]}

机构：

[1] Chinese Acad Sci, Changchun Inst Appl Chem, Electroanalyt Chem Lab, Changchun 130022, Peoples R China

来源：

ELECTROANALYSIS | 1999年 / 11卷 / 15期

关键词：

surface pK(a); self-assembled monolayer of 3-mercaptopropionic acid; gold electrode; cyclic voltammetry; electrochemical titration;

D O I：

10.1002/(SICI)1521-4109(199911)11:15<1108::AID-ELAN1108>3.3.CO;2-Q

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

A self-assembled monolayer (SAM) of 3-mercaptopropionic acid (HSCH2CH2COOH) was formed on a gold electrode. The effect of the charge of the end group on the electrochemical response of Fe(CN)(6)(3-) at the SAM modified electrode was studied by using cyclic voltammetry. At high pH, when the -COOH groups are dissociated, Fe(CN)(6)(3-) current is suppressed; as the solution pH is lowered, Fe(CN)(6)(3-) current increases. The electrochemical titration curve was obtained by correlating the currents to the different electrolyte pH values, from which the surface pK(a) was obtained to be 5.2+/-0.1. Furthermore, a calculation equation was presented to simulate the electrochemical titration. As comparison, the surface pK(a) was also measured by contact angle titration as 5.6+/-0.1. The surface pK(a) values determined by the two methods in our work are consistent and accurate.

引用

页码：1108 / 1111

页数：4

共 23 条

[1] COMPOSITION OF STEARIC AND BEHENIC ACID MONOLAYERS FROM SODIUM-CONTAINING SUBSTRATES [J].