Ion-Selective Electrode Based on a Novel Biomimetic Nicotinamide Compound for Phosphate Ion Sensor

Phosphorus is not only an import nutrient to aquatic habitats, but it also acts as a growth inhibitor in aquatic ecosystems; however, it also aggravates environmental issues, such as eutrophication. There is a growing interest in rapid phosphorus detection to manage and protect water resources. Due to the large molecular structure and high hydration energy of phosphate ions, ion-selective electrodes (ISEs) remain in their infancy for real-time measurements in terms of practical application. In this study, a newly developed ionophore based on a biomimetic nicotinamide functional group was used to detect phosphate selectively, displaying efficient binding through charge interactions and hydrogen bonds. The ISE membrane containing silicone rubber demonstrated an effective detection performance over a long period of time. With a dynamic range between 10^-6 and 10^-2 M and a limit of detection of 0.85 × 10^-6 M (26 μg/L), the newly synthesized ISE membranes demonstrated selectivity for phosphate ions over other ions, including acetate, sulfate, and chloride.