Screen-printed electrode modified with carbon black nanoparticles for phosphate detection by measuring the electroactive phosphomolybdate complex.

We report a sensor for phosphate detection based on screen-printed electrodes modified with carbon black nanoparticles. The phosphate was measured in amperometric mode via electrochemical reduction of molybdophosphate complex. Carbon black nanoparticles demonstrated the ability to quantify the molybdophosphate complex at a low applied potential. Some analytical parameters such as the working solution (sulfuric acid 0.1M), applied potential (0.125V vs Ag/AgCl), and molybdate concentration (1mM) were optimized. Using these conditions, a linear range of 0.5-100µM was observed with a detection limit of 0.1µM, calculated as three times the standard deviation of the blank divided by the slope of calibration curve. The system was challenged in drinking, river, aquarium, and waste water samples yielding satisfactory recovery values in accordance with a spectrophotometric reference method which demonstrated the suitability of the screen-printed electrode modified with carbon black nanoparticles coupled with the use of molybdate to detect phosphate in water samples.