Saeed Rezaei-Zarchi, Leila Mirzaei, Samira Ghobadzadeh, Masoud Negahdary, Gholamreza Mazaheri, Marziyeh Ajdary, Fariba Pishbin,
"In this study, carbon paste electrode (CPE) was modified by single-wall carbon nanotubes (SWNTs) and catalase enzyme (CAT). The modified electrode was used for determination of hydrogen peroxide (H2O2). The SWNT was synthesized by catalytic chemical vapor deposition (CCVD) of methane on the Fe/Co/MgO catalyst and charac-terized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray Diffraction (XRD), Raman spectroscopy and UV-visible spectroscopy. The best experimental condition could result in car-bon yield of 250% and high quality SWNTs with the controlled diameter of 0.9- 2.7 nm and length 5-30ïm and purity more than 90% and less than 3% amorphous carbon were obtained. Direct electrochemistry of catalase enzyme in CPE was easily obtained and a reversible pair of peaks, that are similar, were appeared from Fe (ΙΙ) and Fe (ΙΙΙ) with the formal potential (Eï¢ï°) about +0.045 volts. This electrochemical process occurred in 0.1 M phosphate buffer solution (PBS) at PH=7. The designed sensor with high sensitivity and short response time (less than 8 second), and in the linearity of 3 to 370 ïM can be used to determine the concentration of H2O2"