Controlling the mixed potential of polyelectrolyte-coated platinum electrodes for the potentiometric detection of hydrogen peroxide

Paper‐based Potentiometric Biosensor for Monitoring Galactose in Whole Blood

“…The major drawback of the mixed potential systems is their extreme susceptibility to the chemical environment. However, we have demonstrated that the use of a polyelectrolyte coating overcomes this problem, stabilizing and enhancing the electrode response [30].…”

“…In previous works, we have shown that a platinized paper electrode coated with a layer of an ionomer, such as Nafion®, can be used as a very sensitive and selective potentiometric sensor for hydrogen peroxide and – upon incorporation of glucose oxidase – also for glucose [26]. The working principle of this system, based on a mixed potential mechanism, has been described in more detail elsewhere [30]. In short, in an aqueous solution that lacks of a well‐defined redox couple, the open circuit potential (OCP) of a Pt electrode is determined by the anodic and cathodic exchange currents produced by the surface redox reactions of different solution components.…”

“…The Nafion® coating indeed stabilizes the potential of the platinized paper and allows for the detection of glucose in blood with enhanced sensitivity [28, 29]. We have attributed this enhancement of performance as the stabilization of the mixed potential generated at the platinum electrode interface and the recovery of the original Tafel sensitivity [30].…”

Characterization and Validation of a Platinum Paper‐based Potentiometric Sensor for Glucose Detection in Saliva

“…[30,31]. Recently, our group has reported the use of polyelectrolytes, such as Nafion, as a way to control the mixed potential of the platinum based electrode [32]. The open circuit potential of the Pt electrode is indeed shown to work under kinetic control of the oxygen reduction reaction.…”

Potentiometric Sensing

“…Eleven blood samples were analyzed using this sensor, and a good correlation was found between the potentiometric results and the results measured with a commercial colorimetric kit. The same research group recently presented a qualitative model to describe a mixed potential of such a system . The open circuit potential of the Pt electrode is shown to be under kinetic control of the oxygen reduction reaction.…”