MWCNT-chitosan composite chemically modified electrode as an electrochemical detector for highly selective flow injection analysis of H2O2

Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore-632 014, Tamilnadu, India E-mail : askumarchem@yahoo.com Multi-walled carbon nanotube (MWCNT)-chitosan (CHIT) chemically modified glassy carbon electrode (GCE), designated as GCE/MWCNT-CHIT has been developed by modifying a suspension of MWCNT + CHIT-acetic acid mixture on a cleaned GCE and demonstrated as a selective electrochemical detector (ECD) for flow-injection analysis (FIA) of hydrogen peroxide. The GCE/MWCNT-CHIT showed stable surface confined redox feature at E0´ = –0.22 V vs Ag/ AgCl with surface excess value 13.63 nmol cm–2 in pH 7 PBS. Under an optimal condition, applied potential = –0.2 V vs Ag/AgCl, hydrodynamic flow rate = 0.75 mL min–1 and pH 7 phosphate buffer as a carrier solution, the FIA-ECD showed H2O2 calibration plot in an range 50–2500 µM with detection limit and current sensitivity values 9.7 µM and 0.59 nA µM–1 (0.8345 A M–1 cm–2) respectively. There was no interference from cysteine, ascorbic acid, uric acid, nitrite, and nitrate. A cosmetic cream, clinical H2O2 and milk were further tested as real samples with ~100% recovery values