Electrochemical Characterisation of a Real-Time pH Sensor
In this study a carbon paste electrode (CPE) was modified with a quinone containing diazonium salt by electrochemical deposition. Various deposition conditions were employed to give the optimum and most efficient method. Shown in Figure 1 is a SEM micrograph of a modified CPE alongside the mechanism for the electrodeposition of the diazonium salt onto the electrode.
Figure 2 shows a bare CPE cycled in a PBS solution compared to a modified CPE cycled in the same solution. This indicates that the diazonium salt was successfully deposited onto the electrode surface. Potentiometric pH responses of the modified electrodes showed a response slope of −60.36 ± 0.89 mV/pH, n = 23, as shown in Figure 3. The electrode stability was tested for a period of up to 28 days. Modified electrodes were also subjected to treatment with physiologically relevant proteins and lipids to investigate any implications for real-time monitoring of brain pH.
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