Electrocatalysis detection methods

The concentration of hydrogen peroxide can be measured directly using amperometric detection. A change in H2O2 concentration in the medium appears as a variarion in the output current. The quantified parameters are m nitude of the sensor response, response time, and current response. It is desirable to measure signals in conditions when the linear relationship exists between the current value and the analyte concentration. At that point, the reactions are considered to be in steady state when pseudoequilibrium occurs between the species close to the sensor and their consumption at the indicative electrode. One of the serious problems associated with measurement of complex analytes is the possible interference of the redox species present in the sample. Several methods have been reported which aimed at reducing level of interference. These methods include use of perm-selective coatii, use of artificial mediators, or selective electrocatalysis. The use of mediators or selective electrocatalysis helps to lower the detection potential to the level when the majority of interferii species are electroinactive. ... 

The interface between two immiscible electrolyte solutions offers the means to combine two-phase catalysis, colloid catalysts, and electrocatalysis. In the study of Lahtinen et al. [158] citrate-stabilized palladium and gold colloids were prepared by a traditional chemical reduction method. The voltammetric response of a system with an aqueous colloid and an electron donor in the organic phase revealed an irreversible voltammetric wave as the potential was swept positive. The response was detected only in the presence of both the colloid and the electron-donor DCMFc. The response was concluded to result from heterogeneous charging of the colloid with electrons from DCMFc. 

---