Highly Hydrophilic Polymer Composite Modified Electrode for Trace Copper Detection Based on Synergetic Electrostatic Attractions and Chelating Interactions

A new electrochemical sensor for Cu2+ detection by square wave voltammetry with high sensitivity has been constructed, based on a composite of sodium carboxymethyl cellulose and Nafion. Starting from these two polymers that are rich of hydrophilic groups in backbones, a highly negative‐charged composite has been easily prepared, which displays outstanding ability to adsorb and enrich Cu2+ onto the electrode surface through both electrostatic attractions and chelating interactions. After optimizing test conditions, this new sensor exhibits a good linear signal response to Cu2+ in a concentration range from 1.0 nΜ to 50.0 nM with a limit of detection of 0.6 nM (S/N=3), as well as good anti‐interference for commonly co‐existing metal ions. Besides, this new electrochemical copper sensor has been successfully applied to detect trace Cu2+ in natural water samples with satisfactory recoveries of 98–104 %. These findings provide a new simple but effective way for the determination of heavy metal ions in environmental pollutants.