title: Scanning electrochemical microscopy imaging of rhodochrosite dissolution using gold amalgam microelectrodes.
abstract: Gold/mercury amalgam (Au/Hg) microelectrodes with a diameter of 25 microm were developed for the detection of environmentally relevant analytes such as manganese and iron by scanning electrochemical microscopy (SECM), and applied to investigate the controlled dissolution of manganese carbonate (MnCO(3); rhodochrosite) in acidic conditions. Characterization of the amalgam electrode geometry via approach curves recorded during SECM experiments revealed Au/Hg microelectrodes with sphere cap geometry. Quantitative determination of Mn(2+) has been achieved by calibration of the Au/Hg microelectrode in bulk solution experiments. Subsequent SECM imaging experiments confirm the applicability of amalgam microelectrodes for imaging of Mn(2+) production during dissolution of MnCO(3) at pH 3.9. This study confirms feasibility and provides the fundamental basis of SECM imaging with amalgam microelectrodes to address biogeochemically relevant questions.
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Rudolph
authors.forename: Stephanie
authors.initials: S
authors.lastname: Neuhuber
authors.forename: Christine
authors.initials: C
authors.lastname: Kranz
authors.forename: Martial
authors.initials: M
authors.lastname: Taillefert
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff
mesh_terms: D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D019015:Geologic Sediments / Q000737:chemistry*; D017612:Gold Compounds; D007501:Iron / Q000032:analysis; D008345:Manganese / Q000032:analysis; D008628:Mercury; D008839:Microelectrodes; D014131:Trace Elements / Q000032:analysis*
chemical_list: D017612:Gold Compounds; D014131:Trace Elements; D008345:Manganese; D007501:Iron; D008628:Mercury