• 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 Mar 31, 2017, 2:50 PM by WJ C
Showing posts 1 - 1 of 8. View more »


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

  • Bryce joined the team during summer, welcome. A new UWM student, Bryce Baker, joined the team during summer. Welcome Bryce. 
    Posted Jul 12, 2017, 1:01 PM by WJ C
  • Dr. Seok Min Kim will give a seminar in 4/7/2017 Dr. Seok Min Kim will give a seminar entitled "Fabrication of glass molded micro/nano structures using vitreous carbon mold" from 3:30 pm to 4:30 pm in EMS ...
    Posted Mar 31, 2017, 2:45 PM by WJ C
  • Tae Joon received Distinguished Graduate Student Fellowship Tae Joon received Distinguished Graduate Student Fellow 2017-2018. Congratulations. Congratulations for others too. 
    Posted Mar 31, 2017, 2:40 PM by WJ C
  • 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 WJ C
  • 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 WJ C
Showing posts 1 - 5 of 35. View more »