Polarography

About: Polarography is a research topic. Over the lifetime, 4772 publications have been published within this topic receiving 75478 citations.

Second-harmonic alternating current polarography

Abstract: The technique of second-harmonic a.c. polarography is discussed from the viewpoints of theoretical basis, experimental requirements, and scope of application. The theoretical relation is given for the second-harmonic current-component of a straightforward electrochemical reaction under conditions of a.c, polarography. It is shown how this relation can be used to determine the kinetic parameters (rate constant and transfer coefficient) of the electron-transfer step. Results obtained with the zinc(n)/zinc (mercury) system are in good agreement with those reported in other investigations by other methods. The experimental aspects of second-harmonic studies are examined, and the dependence of the accuracy and reliability of results on various features of the instrumental arrangement is brought out. Potential applications, particularly in tensammetric studies and in analytical work, are indicated.

Barbituric Acid Sensor Based on Molecularly Imprinted Polymer‐ Modified Hanging Mercury Drop Electrode

Abstract: A barbituric acid sensor based on molecularly imprinted polymer-modified hanging mercury drop electrode is reported for sensitive and selective analysis in aqueous and blood plasma samples. It was developed by coating directly the barbituric acid- imprinted polymer, which is prepared from melamine and chloranil, onto the surface of a hanging mercury drop electrode under charge-transfer interaction at +0.3 V (vs. Ag/AgCl) in Model 303A electrode system connected with a polarographic analyzer/stripping voltammeter (PAR Model 264A). The binding event of barbituric acid was detected in the imprinted polymer layer through differential pulse, cathodic stripping voltammetric (DPCSV) signal at optimized operational conditions [accumulation potential +0.3 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0 (without supporting electrolyte), scan rate 10 mV s−1, pulse amplitude 25 mV]. The limit of detection for barbituric acid was found to be 0.54 ppm (RSD=3.7%, S/N=3). The detection was feasible without any problem of matrix effect or cross reactivity in the linearity range of concentration varying from 0.50 to 125.00 ppm of barbituric acid.

Voltammetric determination of total dissolved iron in coastal waters using a glassy carbon electrode modified with reduced graphene oxide, Methylene Blue and gold nanoparticles

Abstract: A nanocomposite, prepared from reduced graphene oxide (rGO), Methylene Blue (MB) and gold nanoparticles (AuNPs), was used to modify a glassy carbon electrode for the determination of total dissolved iron by differential pulse voltammetry. The use of rGO warrants a larger electrode surface and the presence of more active sites, while electron transfer is accelerated by incorporating AuNPs. MB acts as an electron mediator, as an anchor for the AuNPs (which were grown in situ), and also prevents the aggregation of rGO. The modified electrode displayed a remarkably improved sensitivity and selectivity for Fe(III). The kinetics of the electrode reaction is adsorption-controlled, and the reversible process involves one proton and one electron. The response to Fe(III) is linear in the 0.3 to 100 mu M concentration range, and the detection limit is 15 nM. Possible interferences by other ions were studied. The electrode was successfully applied to the determination of total dissolved iron in real coastal waters.