Electrochemical Detection of Manganese in Drinking Water with Chronoamperometry

Methods for detecting contaminants in drinking water are crucial for protecting public health. Despite manganese (Mn) being an essential mineral for humans, Mn in high concentrations is suspected of being associated with negative cognitive and neurological effects on humans, especially on children. Current methods of detection, though reliable, are limited in the application to real-time easy-to-use, field or bench-top monitoring applications for testing drinking water. Herein, chronoamperometry (CA) is explored to quantitatively analyze manganese samples for drinking water applications. CA proved to be effective at measuring the concentration of Mn²⁺ in water samples with excellent recovery rates (97.8%) and reproducibility between electrodes. With 1-min deposition using bare gold electrodes, CA was able to obtain a detection limit of 34.3 µM. Furthermore, with a 5-min deposition using bare gold electrodes, CA was able to obtain a detection limit of 4.64 µM. This new CA method also offers a simplified cleaning method that will allow electrodes to be used continuously for differing samples or replicate tests. The cleaning procedure permits the reuse of electrodes, while simultaneously eliminating the need for special surface modifications on the electrodes. Ultimately, this cleaning procedure offers a faster and more efficient procedure than previous methods such as polishing. The CA method also demonstrated minimal interference effects when tested with varieties of water hardness, ionic strength, common electroactive species (Cu²⁺, Fe²⁺, Fe³⁺, and Cl⁻), and organic matters in aqueous environments. This CA method is easy to use, requires portable equipment, uses reagents that are easily accessible, and does not require extensive sample preparation.