Polyaniline Langmuir–Blodgett film modified glassy carbon electrode as a voltammetric sensor for determination of Ag+ ions

Electrochemically induced regioregularity of the binding sites of a polyaniline membrane as a powerful approach to produce selective recognition sites for silver ion

“…At very low pH, the membrane becomes positively charged causing repulsion of silver ions. The interpretations are in agreement with the previous reports [21,27,54]. The decrease in DPASV peak current at higher pH values can be ascribed to: (i) decreasing the electroactivity and conductivity of PANI; and (ii) formation of insoluble silver hydroxide species.…”

“…In the case of a templated electrode, 10-fold of Hg 2+ was found to enhance the DPASV signal of silver; but on the untemplated electrode, 1-fold of Hg 2+ increased the stripping signal of silver. This enhancement in DPASV peak current can be related to the simultaneous reduction and stripping of Ag + and Hg 2+ in the preconcentration and DPASV steps [27,60]. In our experiments, one DPASV peak was obtained for the mixture of Ag + and Hg 2+ .…”

“…Mercury (II) caused interference for the proposed silver selective electrode ( Table 2). The higher selectivity of the electrode for Ag + and Hg 2+ ions with respect to other ions can be attributed to various factors; (1) silver and mercury ions are soft acids and have high affinity for interaction with π electrons of both PANI and SSA [33,61]; (2) Ag + and Hg 2+ effectively coordinate with the N atom of PANI and binding sites of SSA [27,62]; and (3) during the templating process, proper recognition sites for silver ion are formed throughout the PANI/SSA membrane as a result of the guestinduced reorientation of binding sites of the membrane. The selectivity pattern of the membrane strongly depends on the templating process.…”

“…If the counter anion is large and has low mobility, it cannot be released from the polymeric membrane and its presence leads to incorporation of the electrolyte cations into the membrane in order to equilibrate the charge [26]. Therefore, it is possible to improve the cationic selectivity of the polymeric membranes by adjusting the size of the counter anion used in the electropolymerization procedure [27].…”

“…Potentiometric sensors based on PANI and thiacalix [4]arenes [34,35], and PANI dispersion cast on an insulating plastic support [15] have been applied for determination of silver ions. A voltammetric sensor made of a Langmuir-Blodgett film containing PANI doped with p-toluenesulfonic acid has been used for the detection of silver ion [27].…”