A gold-based mercury microelectrode was prepared by electroreducing Hg2+ on a gold wire of 25 μm diameter encased in glass. The electrode reaction and analytical sensitivity for dissolved O2, Mn, Fe, S (-II), and H+ using square wave voltammetry are investigated. The use of this voltammetric microelectrode takes advantage of fast scan voltammetric methods for the simultaneous measurement of the key redox species during a single potential scan from -0.1 V to -1.7 V (SCE). Various interfering factors and experimental parameters of the voltammetric measurements are discussed. By mounting the working electrode on a computerized micromanipulator, vertical microprofiles of the redox species were measured at 10 μm depth resolution across seawater biofilms formed on metal coupons. Results revealed the heterogeneous nature of the biofilm and complex microbially mediated heavy metal (Mn and Fe) cycles within the biofilm system. Data interpretation provided further insight into the mechanism of the microbially influenced metal corrosion.

Subject
Electric current, Microelectrodes, Metal surfaces, Waves, Seawater, Voltammetry, Biofilms, Mercury, Electrochemical current, Oxygen, Risk reduction, Electrodes, Electrode potential
Keywords:
biofilm, biocorrosion, microelectrode, square wave voltammetry, redox species, microprofile
© 1997 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1997
Association for Materials Protection and Performance (AMPP)
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