Gunnar Olsen, Jens Ulstrup and Qijin Chi
NanoChemistry group, Department of chemistry, DTU, Denmark
Reduced graphene oxide (RGO) offers a low-cost alternative to pristine graphene with high potential for mass-production . Furthermore, RGO is easier to be functionalized with desired molecular groups, which is a key step to provide high selectivity and sensitivity in chemical and biochemical sensing applications [2-3]. In this work, we have focused on the synthesis of a 1-Aza-18-crownether functionalized RGO (RGO-crown),leading to specific binding site for potassium ion on the RGO surface. When RGO-crown is used to functionalize an electrode, the electrode can be used for selective potentiometric sensing of potassium ions. This has been tested both on glassy carbon electrode (GCE) and on cheap disposable screen printed electrode (SPE), with a detection limit of 10-5 M without inference from other ions (Na+ Li+ NH4+ and Ca2+) in concentrations up to 2.5 10-2 M. The results demonstrate that RGO-crown is a conductive material full of promising for application in fabrication of ion selective sensors.
 S. Stankovich et al., Carbon 45, 1558–1565 (2007)
 J. D Fowler et. al., ASC Nano 3, 301-306 (2009)  M.Pumera, A. Ambrosi, A. Bonanni, E. L. K. Chng, H. L. Poh, Trends Anal. Chem. 29, 954-965 (2010
Gunnar Olsen is currently a 3rd year PhD student (2013-2016) in the Nanochemistry group at DTU chemistry. His current research interest focuses on organic functionalization of reduced graphene oxide to synthesize new hybrid materials for their applications in chemical sensing. He has research experience and background in synthetic organic chemistry with B.Sc. (2010) and M.Sc (2012) degrees from South University of Denmark (SDU), where he synthesized tetrakis-tetrathiafulvalene-calixpyrrole and studied their supramolecular interaction.