This review is based on a critical approach to the potential values applied for detection in amperometric biosensor systems developed mainly to detect phosphate ion concentration, an important indicator parameter in environmental and biological systems. The basic working principle of amperometric phosphate biosensors widely studied for phosphate detection has been explained. The literature on the subject, particularly about applied potential, has been examined and discussed in detail. It has been concluded that each study utilized different potential values to measure phosphate and no detailed research was conducted regarding the selection of these values. Most studies indicate that the phosphate signal depends on the redox of H2O2. However, detailed potential scanning experiments have not been carried out for H2O2 alone in those studies. It has been concluded that H2O2 undergoes oxidation or reduction based solely on theoretical information. In the interference and real sample tests, it has been observed that the behavior of different interfering substances within a certain potential range was not examined. Only the percentage effects of the interference on the phosphate signal have been mentioned in the studies. Furthermore, the effect of interfering substances on the electrode surface at the given potential has not been examined. This review study also presents experimental recommendations for future studies to address the deficiencies in the literature.