CAREER NETWORK World's one of the largest Research Career Network Benefits Academic & Industry jobs Project funding Visiting faculty positions Visiting scientist positions Invited talks and more... Register FREE Chemical Sensors 2011, 1: 18 Research Article Electrochemical investigation of glassy carbon paste electrode and its application for guanine and ssDNA detection Abdel-Nasser Kawde, Tawfik A. Saleh Center of Excellence in Nanotechnology, and Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261, KSA Abstract A glassy carbon paste electrode (GCPE) is fabricated and investigated by studying the electrocatalytic behavior of ferrocyanide redox couple on its surface by using cyclic voltammetry (CV). The GCPE showed voltammetric responses with high sensitivity and low background compared with both glassy and graphite carbon electrodes. It also showed a distinct oxidation peak at +0.9V after preconcentration of guanine at +0.5V for 1.0 min in pH 4.3 acetate buffer solution (0.1M). This paper also reports the use of square wave voltammetry (SWV) for monitoring guanine. A linear dynamic range of 0.5 to 50 µg/ml for guanine is obtained with R2 = 0.995, the intra-day precision RSD = 1.90% (n = 7) and inter-day precision RSD= 2.98% (n = 6). A detection limit of 50 ng/ml was obtained. The SWV studies using the GCPE showed two well-resolved peaks for guanine and adenine in ssDNA at +1.05 and +1.30 V respectively, revealing the applicability of the GCPE for electrochemical detection of ssDNA. A linear range of 1.0 - 10.0 µg/ml with the detection limit 100 ng/ml, R2 = 0.993 for guanine and 0.992 for adenine was obtained. The inexpensive and easy to prepare GCPE offers a high electrochemical activity and a relatively low background current. Keywords Cyclic voltammetry; Square wave voltammetry; Glassy carbon paste electrode; Guanine; ssDNA