A Comparative Study of Electroanalytical Methods for Detecting Manganese in Drinking Water Distribution Systems

Abstract

Manganese (Mn) is an emerging contaminant in drinking water as recent studies show its detrimental neurological impacts in children, prompting more stringent regulatory requirements. Many aspects of Mn accumulation and release in the distribution system remain enigmatic, as the current suite of analytical tools is not practical for real-time monitoring. In order to manage Mn in distribution systems effectively, a practical monitoring technology must be developed. In this comparative study, we have explored three electroanalytical techniques for Mn detection as they have the potential to act as rapid, low-cost, real-time sensors. Glassy carbon electrode (GCE) was selected, in part due to their non-toxic properties, for use with three different electrochemical techniques, cyclic voltammetry (CV), cathodic stripping voltammetry (CSV), and electrochemical impedance spectroscopy (EIS). CSV provided limits of detection (LOD = 0.43 µM) between the maximum allowable concentration (MAC = 2.18 µM) and aesthetic objective (AO = 0.36 µM) for drinking water. Although CV only provides LOD of 74 µM (above MAC and AO), it shows good performance in high Mn concentrations and provide rapid measurements on Mn. EIS provided non-Mn specific metal ion detection with an LOD of 2.2 µM. The study provides proof of concept that GCE in combination with electroanalytical techniques could be further optimized for practical application for monitoring Mn in drinking water and protecting public health.