The Effects of Temperature and pH on the Responses of Glutamate Oxidase Based Biosensor

Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system (CNS). It’s playing a major role in a wide variety of brain functions. However, increasing of the extracellular concentration of glutamate leads to excitotoxicity. Thus there is a need for rapid and sensitive methods to detect it in both clinical and food samples. In this research for measurement of glutamate release, a glutamate biosensor is fabricated using immobilizing of glutamate oxidase at the surface of platinum electrode. Since temperature and pH have a great effect on glutamate oxidase activity and fabricated biosensor performance, for this reason, the effects of temperature and pH on the responses of fabricated biosensor are investigated using cyclic voltametry method. The temperature effect on the responses of fabricated biosensor was evaluated between 25±1 °C and 75±1 °C and scan rate 10 mv/s using cyclic voltametry method. Also, the pH effects on biosensor’s responses were evaluated in the range of 5.5 to 9.5. All experiments were performed in the buffer phosphate (0.1 M), 0.5 × 10-3 M glutamate. The results showed that the best response of fabricated biosensor was happened at 45°C and pH 7.4. So that, this temperature selected as working temperature for all further experiments. It is important to note that, pH 7.4 in which 14th Annual Electrochemistry Seminar of Iran Materials and Energy Research Center (MERC), 12- 13 Dec, 2018 73 obtained in this research, completely agrees with the optimum pH of glutamate oxidase catalytic activity.