Voltammetric analysis of weak acids with microelectrodes

被引：20

作者：

Canhoto, C ^{[1
]}

Matos, M ^{[1
]}

Rodrigues, A ^{[1
]}

Geraldo, MD ^{[1
]}

Bento, MF ^{[1
]}

机构：

[1] Univ Minho, Dept Quim, P-4710057 Braga, Portugal

来源：

JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 2004年 / 570卷 / 01期

关键词：

weak acids analysis; microelectrodes; voltammetry;

D O I：

10.1016/j.jelechem.2004.03.015

中图分类号：

O65 [分析化学];

学科分类号：

070302 ; 081704 ;

摘要：

The role of H+ on the steady-state voltammetric limiting current (I-L) of weak acid (HA) reduction was studied considering results from either lactic acid or acetic acid solutions at constant pH. For solutions with pH > pK(a) or pH congruent to pKa the [H+] effect on the I-L vs c(HA) slope was important even when the H+ current contribution was minor. In contrast, when the pH < pK(a) high H+ current contributions were found; nevertheless the I-L VS c(HA) slope was almost insensitive to pH. A general relationship between I-L and c(HA) was derived considering both the H+ current contribution and the dissociation extent. This equation allows the analytical determination of weak acids, alone or in the presence of strong acids, from experimental I-L and pH. Acid identification can also be performed through the expression presented, following the I-L susceptibility to pH at constant c(HA). (C) 2004 Elsevier B.V. All rights reserved.

引用

页码：63 / 67

页数：5

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