Electrooxidation of Hexacyanoferrate(II) Anions and Electroreduction of Oxygen in the Microfabricated Electrochemical Sensor-Array System

Abstract

The microfabrication technique was used to prepare a six-channel sensor-array chip. The sensor-array has been fabricated using borosilicate wafer containing Pt electrodes and connection pads and the silicon wafer with through holes, which were bonded with SU-8 using adhesion bonding method. To characterize the prepared sensor-array chips the cyclic voltammetry and electrochemical impedance experiments were carried out in a three-electrode electrochemical system. The electrooxidation of ferrocyanide and electroreduction of oxygen were studied. It was shown that the measured current density depends on the electrode potential sweep rate however, both linear and radial diffusion mass transfer components are important at high electrode potential scanning rate. The pseudo steady-state conditions were achieved at slow potential sweep rates (>0.01 V s -1 ) and the electrodes behaved as the microelectrodes. The pseudo steady-state current density is proportional to the concentration of electroactive species. The recessed microdisc electrode model has been used to describe the system.

Evaluation of multiple linear regression applied to impedimetric sensing

“…MLR has already been successfully applied in electroanalysis, but its scope is quite restricted to voltammetric methods 23–26 . The methodology was first evaluated in the quantification of ferrocyanide, a redox probe with well‐reported electrochemical behavior 27,28 . Following, the methodology was applied in the individual quantification of catechol and hydroquinone in the direct analysis of spiked tap water samples.…”

Three-dimensional voltammetry: Use of chronoamperometric E-t-i data to achieve second-order advantage

“…The work presented here aimed at the evaluation of E-t-i data in association with secondorder calibration techniques in the development of electroanalytical methods. The methodology was initially evaluated with a model problem, namely the determination of ferrocyanide -a wellknown redox probe with well-reported electrochemical behavior [23,24] -in the presence of hydroquinone, as a strong interferent not included in the calibration step. Ferrocyanide and hydroquinone show highly overlapped voltammetric peaks, but distinct oxidation processes regarding electron transfer.…”