Electrodeposition of Co-Mo Alloys and Its Applications in Electrochemical Sensing of Phosphate

Quantification of phosphate ions in water ecosystems is crucial for maintaining a healthy aquatic environment and optimizing aquaculture parameters. While cobalt (Co) thin film modified electrodes are widely used as phosphate sensors, their selectivity and stability often require improvements for on-site measurement. The present work addresses this challenge by introducing a novel phosphate sensing platform utilizing Cobalt-Molybdenum (Co-Mo) alloy film deposited on copper substrate. The developed Co-Mo thin film sensor exhibited a good thermal stability (up to 60 °C) and significantly improved the detection ranges (10 −6 M to 10 −2 M). The influence of electrolyte pH and temperature toward potentiometric sensing of phosphate were investigated and the conditions were optimized to improve the sensor sensitivity. The sensor showed a sensitivity of −56 mV.dec −1 with a good correlation coefficient (0.988). The detection limit was determined to be 0.987 μM and the relative standard deviation (RSD) was 1.3% (n = 3). The Co-Mo thin film sensor exhibited negligible interference even in the presence of 10-fold excess concentrations of common interfering analytes, demonstrating its robust performance in real-world environment. To validate the field practicality, the sensor’s performance was successfully tested in real shrimp culture water samples, demonstrating its compatibility with complex environmental matrices.