| 摘要 |
A phosphate sensor 1 for sensing phosphate in solution 2 comprises a first electrode 3 with a cobalt surface immersed in the solution to generate an electrical potential, and a second electrode 4 electrically connected to the first electrode comprising a non-cobalt surface. Voltage source 11 is arranged to apply a voltage between the electrodes such that the electrical polarity of the first electrode is negative relative to that of the second electrode, thus maintaining a protection voltage to prevent cobalt oxidation. Reference electrode 5 is arranged for immersion in a reference solution to generate a reference electrical potential. Switch 12 is operable selectively to connect the reference electrode to the first electrode. An electrical potential difference between the first electrode and the reference electrode is detected when connected by the switch. A detection signal is output indicative of a detected phosphate concentration level according to the detected potential difference. |
