Development of cobalt-carbon-based potentiometric phosphate sensors using cyclic voltammetry with potential scan rate variations

Abstract

Phosphate sensor development is still needed because there are not many available in the field offering fast detection on environment, medicine, and agriculture. Herein, this study reported the potentiometric sensing of phosphate ions using a cobalt-carbon electrode. Cobalt was electrodeposited in the surface of carbon-producing cobalt-carbon electrodes using cyclic voltammetry at various scan-rate using Ag|AgCl as reference electrode and assisted by ionic strength adjustor 0.0025 M at pH 4. The electrode was characterized based on morphology and crystallinity. Then, the potentiometric sensing performance was evaluated using a Cobalt carbon electrode as a working electrode for phosphate ions in various concentrations. The results showed the homogeneous particle size observed at a scan rate of 5 mV/s. Besides, all the scan-rate variations produced an amorphous structure. The greatest potentiometric slope was −34.2 mV/decade on the electrode produced at a scan rate of 1 mV/s. The electrode reproducibility test produced the highest coefficient of variation value of 0.77 %.