Electrochemical interference study of manganese and iron by multiplex method and the application for manganese analysis in drinking water

Abstract

Manganese is an emerging concern in drinking water, due to its potential health and aesthetic effects. Although accurate and sensitive, spectroscopic techniques for Mn2+ detection are costly and not capable of rapid detection. Electrochemical methods, such as cathodic stripping voltammetry, have been intensively explored as portable low‐cost methods for Mn2+ detection. Challenges of reliability and matrix interference are difficult to overcome with current electrochemical methods. Among the interference reagents, Fe2+ is one of the biggest challenges for Mn2+ detection. Herein, a new method based on multiplex chronoamperometry at potentials between 0.9 and 1.4 V by a multichannel potentiostat is explored for its ability for interference resistance and applicability for Mn2+ detection in real drinking water samples. Compared to conventional one‐channel electrochemical techniques, the multiplex method generates a reliable pattern that is unique to the sample components. The interference between Mn2+ and Fe2+ is investigated and the results are promising even at 100:1 Fe2+:Mn2+ concentrations. The detection limit determined for the multiplex method was 25.3 μM, and the optimum recovery rate in a real drinking water sample was 99.8%.

Enhancing Sensitivity of Manganese Detection in Drinking Water Using Nanomaterial AuNPs/GP

“…25 The peak suppression of Mn 2+ was due to the competing oxidation reaction of Fe 2+ . 17 When the Fe 2+ concentration is 100 times the concentration Mn 2+ , the Mn 2+ CSV peak current decreased by 99.3%. Mn 2+ detection using CA is also affected by the presence of Fe 2+ , due to the oxidation reaction of Fe 2+ at the oxidative potential.…”

“…16 To overcome the peak suppression due to Fe 2+ interference, we developed a pattern recognition approach using multiplex CA analysis. 17 Other than Mn 2+ detection, CA also has a long history of combining high-performance liquid chromatography as an electrochemical detector to analyze oxidation-reduction (redox) active compounds. 18,19 CA has shown great promise to detect analytes qualitatively or quantitatively, thus the performance of CA for Mn 2+ detection is worth comparing with an established electrochemical technique (i.e., CSV).…”