Fabrication and Use of Dual‐function Iridium Oxide Coated Gold SECM Tips. An Application to pH Monitoring above a Copper Electrode Surface during Nitrate Reduction.

Abstract

The fabrication of a gold microelectrode modified with iridium oxide film (IrOx) and its use as tip with a dual function in SECM experiments is reported. The defective structure of the coating onto the microelectrode surface was used as strategy to combine the advantages of both amperometric (for current‐distance determination) and potentiometric (for pH sensing) SECM operation modes. Approach curves, using oxygen and hexaammineruthenium(III) as redox mediators, were obtained without significant loss of the performance and reproducibility of the potentiometric pH response. This allowed the precise positioning of the proposed tip above a substrate in SECM experiments and, subsequently, to monitor pH at the substrate surface. The IrOx modified microelectrode was applied successfully in SECM experiments involving the local proton consumption during the nitrate reduction at a copper cathode surface.

Review of Electrochemical DNA Biosensors for Detecting Food Borne Pathogens

“…Changli Zhong et al [149] developed an electrochemical biosensor based on hairpin assembly amplification to detect specific DNA with high sensitivity and specificity. MCH and BSA were used to block the non-specific adsorption sites jointly.…”

Die lokalen Aktivitäten von Hydroxidionen und Wasser bestimmen die Funktionsweise von auf Silber basierenden Sauerstoffverzehrkathoden

“…Dort agieren sie als Sensor fürl okale OH À -Ionenaktivitäten und lokale pH-¾nderungen (Abbildung 1). Anders als in vorherigen Studien zu lokalen pH-Messungen [15] bençtigt die hier vorgeschlagene Methode keine zusätzliche Elektrodenmodifikation. Dadurch sind wir in der Lage,lokale ¾nderungen der Ionenaktivitäten in der Nähe der SVK-Oberfläche in stark alkalischem Medium durch voltammetrische Messungen an der Pt-Mikroelektrode als Funktion des an der SVK angelegten Potentials zu bestimmen.…”

Fabricação, caracterização e aplicação de pontas de prova eletroquímicas multifuncionais para técnicas de microscopia de varredura de ponta de prova eletroquímica

“…This general definition reflects the general nature of multifunctional electrochemical probes which the type, shape, size and form depends on the information being acquired simultaneously. Hence, multifunctional probes can be a single electrode, 52 a single pipette, 19 a double or quad barrel pipette, [53][54][55] two or more electrodes in a side-by-side 44 or ring-disc 22,45,56 configuration or any combination of the those (Figure 1.14). 16,57 By using the SICM signal as a positional (z axis) feedback, electrochemical information can be collected over the SECM electrode at a constant electrode/substrate separation allowing pure electrochemical information, free from topography influences, to be acquired.…”