A voltammetric analysis of doxycycline was developed using DNA immobilized onto a carbon nanotube paste electrode (PE). An anodic peak current was indicated at 0.2 V (versus Ag/AgCl) in a 0.1M NH4H2PO4 electrolyte solution. The linear working range of the cyclic and square wave stripping voltammetry was obtained to 1-27 ngL-1 with an accumulation time of 800 s. Final analytical parameters were optimized to be as follows: amplitude, 0.35 V; frequency, 500 Hz; and pH, 5.43. Here detection limit was found to be 0.45 ngL-1, this result can be applied in foods systems and in the biological diagnostics

• Suw Young Ly(Biosensor Research Institute, Seoul National University of Technology. 172, gongreung 2 dong, Nowon gu, Seoul, Korea 139-743)
• Chang Hyun Lee(Department of Integrated Enviromental Systems, Pyeongtaek University, Gyeonggi do, Korea 17869)