title: Spirally oriented Au microelectrode array sensor for detection of Hg (II).
abstract: A simple and reproducible carbon microelectrode array (CMA), designed to eliminate diffusive interference among the microelectrodes, has been fabricated and used as a frame to build a gold (Au) microelectrode array (GMA) sensor. To prepare the CMA initially, rather than use an uncontrollable large number of carbon fibers, only 60 carbon fibers of regular size were used to ensure manageable and reproducible arrangement for array construction. In addition, for efficient spatial arrangement of the microelectrode and easy sensor preparation, carbon fibers were oriented in a spiral fashion by rolling around a Cu wire. The distance between carbon fibers was carefully determined to avoid overlap among individual diffusion layers, one of the important factors governing steady-state current response and sensor-to-sensor reproducibility. After the preparation of a spirally arranged CMA, Au was electrochemically deposited on the surface of individual carbon electrodes to build a final GMA sensor. Then, the GMA sensor was used to measure Hg(2+) in a low concentration range. Simultaneously, multiple GMA sensors were independently prepared to examine reproducibility in sensor fabrication as well as electrochemical measurement (sensor-to-sensor reproducibility). Overall, highly sensitive detection of Hg(2+) was possible using the proposed GMA sensor due to efficient arrangement of microelectrodes and the sensor-to-sensor reproducibility was superior owing to simplicity in sensor fabrication.
authors.affiliation: Department of Chemistry and Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Tran Ngoc
authors.initials: TN
authors.lastname: Huan
authors.forename: Le Quoc
authors.initials: le Q
authors.lastname: Hung
authors.forename: Vu Thi Thu
authors.initials: VT
authors.lastname: Ha
authors.forename: Nguyen Hoang
authors.initials: NH
authors.lastname: Anh
authors.forename: Tran
authors.initials: T
authors.lastname: Van Khai
authors.forename: Kwang Bo
authors.initials: KB
authors.lastname: Shim
authors.forename: Hoeil
authors.initials: H
authors.lastname: Chung
mesh_terms: D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D002413:Cations, Divalent; D003300:Copper; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008839:Microelectrodes; D008855:Microscopy, Electron, Scanning; D017942:Nitric Acid; D015203:Reproducibility of Results; D012996:Solutions
chemical_list: D000077482:Carbon Fiber; D002413:Cations, Divalent; D012996:Solutions; D017942:Nitric Acid; D002244:Carbon; D006046:Gold; D003300:Copper; D008628:Mercury