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Visualization of the Reaction Zones Between Two Miscible Solutions with Potentiometric and Amperometric Microsensors
Author(s) -
Schröck Konstanze,
Schulte Albert,
Schuhmann Wolfgang
Publication year - 2005
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200403186
Subject(s) - potentiometric titration , scanning electrochemical microscopy , microelectrode , amperometry , aqueous solution , chemistry , analyte , analytical chemistry (journal) , electrode , electrochemistry , chromatography , organic chemistry
Abstract A strategy for visualizing the concentration gradients in the border zone between two miscible aqueous solutions of different composition is presented. To achieve this goal, potentiometric pH microsensors and disk‐shaped Pt microelectrode have been operated as scanning probes in a set‐up that combined conventional scanning electrochemical microscopy (SECM) equipment with an inverted optical microscope and a syringe pump for analyte injection. With the established system, complex gradients in proton concentration have been examined in the reaction zone between two aqueous solutions of different pH value, one of which being dispensed into the other at controlled flow rate. In addition to the local potentiometric measurements, Pt microelectrodes have been used as amperometric SECM tips to visualize the reaction zone at the diffuse boundary between a stream of H 2 O 2 and a neighbouring catalase‐containing buffer solution.