Polyphenylalanine-Modified Electrode Enabled Sensitive and Selective Detection of Cadmium Ions in Environmental Water

A novel electrochemical sensor for cadmium ions (Cd2+) was fabricated by electropolymerizing L-phenylalanine on a glassy carbon electrode (PPhe/GCE). The resulting polyphenylalanine (PPhe) film combines a conductive polymer backbone with abundant amino/carboxyl groups for coordination and aromatic rings for π-cation interactions, offering synergistic pre-concentration for Cd2+. Under optimized conditions, the sensor exhibited a wide linear range from 0.50 to 500 μM, a detection limit of 0.115 μM, high selectivity, and good reproducibility. Determination of Cd2+ in spiked lake water samples with recoveries of 96.2%–102.2% demonstrates its potential for environmental water monitoring.