• Highly Selective Mercury Detection

    Partially oxidized graphene flakes (po-Gr) were obtained from graphite electrode by an elec-trochemical exfoliation method. As-produced po-Gr flakeswere dispersed inwater with the assistance of poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonate) (PEDOT:PSS). The po-Gr flakes and the po-Gr/PEDOT:PSS nanocomposite (po-Gr/PEDOT:PSS) were charac-terized by Raman spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), UV–Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). In addi-tion, we demonstrated the potential use of po-Gr/PEDOT:PSS electrode in electrochemical detection of mercury ions (Hg2C) in water samples. The presence of po-Gr sheets in PEDOT:PSS film greatly enhanced the electrochemical response for Hg2C. Cyclic voltam-metry measurements showed a well-defined Hg2C redox peaks with a cathodic peak at 0.23V, and an anodic peak at 0.42V. Using differential pulse stripping voltammetry, detec-tion of Hg2C was achieved in the range of 0.2–14mM(R2 D0.991), with a limit of detection of 0.19mM for Hg2C. The electrode performed satisfactorily for sensitive and selective detection of Hg2C in real samples, and the po-Gr/PEDOT:PSS film remains stable on the electrode surface for repeated use.Therefore, our method is potentially suitable for routine Hg2C sensing in environmental water samples.

    Posted Feb 13, 2016, 7:42 PM by Woo-Jin Chang
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Bionanotechnology, Biomedical Engineering, Biochemical Engineering, BioMEMS,  Biosensor, Bioseparations

  • BioMEMS devices and Biosensors development
  • Separation and identification of biomolecules including protein and human cancer and stem cells
  • Wearable diagnostic health monitoring device 
  • Rapid on-site environmental monitoring device


  • Tae Joon Kwak, Maria Alejandra Najera, Young Gyu Nam, Sang Woo Lee, J. Rudi Strickler, and Woo-Jin Chang (corresponding author), Convex Grooves in Staggered Herringbone Mixer Improve Mixing Efficiency of Laminar Flow in Microchannel, PLoS One, 11(11), e0166068, 2016. 
  • Jiang Yang, Tae Joon Kwak, Xiaodong Zhang, Robert McClain, Woo-Jin Chang (co-corresponding author), Sundaram Gunasekaran, Combining pH strips and meters: a hand-held electrochemical paper-fluidic pH platform using nanoparticle-anchored iridium oxide-reduced graphene oxide hybrid thin film, ACS Sensors, 1(10), 1235-1243, 2016. 

Recent News

  • Dr. Seok Min Kim joined the group Dr. Seok Min Kim, a professor in Chung-Ang University in Korea, join the group during his sabbatical from August 2016. Welcome Dr. Kim.
    Posted Jan 4, 2017, 11:27 AM by Woo-Jin Chang
  • Lauren and Dylan joined for the summer Lauren and Dylan joined the group for the summ, 2016. Welcome.
    Posted Nov 5, 2016, 1:18 AM by Woo-Jin Chang
  • Jongwon, Rizwen, Misong Joined Jongwon, Rizwen, and Misong joined the group since Spring 2016.  Welcome.
    Posted Feb 13, 2016, 7:06 PM by Woo-Jin Chang
  • MOU between City of Milwaukee and Daegu City in Korea City of Milwaukee and Daegu Metropolitan City in Korea signed agreement to foster water industry
    Posted Nov 3, 2015, 5:52 PM by Woo-Jin Chang
  • Korean delegation from Daegu City visited Milwaukee Korean delegation from Daegu Metropolitan City in Republic of Korea visited Milwaukee to attend the Water Summit from June 21 to 25, 2015.
    Posted Aug 5, 2015, 8:48 AM by Woo-Jin Chang
Showing posts 1 - 5 of 32. View more »