Selective electrochemical detection of ascorbic acid in canned juice using aniline/N-(1-naphthyl)ethylene-diamine modified MWCNT electrode

Environmental and Analytical Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology University, Vellore-632 014, Tamilnadu, India E-mail : askumarchem@yahoo.com Selective electrochemical detection of ascorbic acid (AA) in fruit juice is an important analytical problem. Since electrochemical techniques offer an easy extension to portable device, design and development of new chemically modified electrodes, which can able to sense AA is most wanted in quick quality control assessment. Herein we report, an electro-copolymerized aniline/N-(1-naphthyl)ethylene-diamine (NED) on MWCNT modified gold electrode (Au/ MWCNT@PANI-NED) in a neutral pH solution for highly efficient and low potential detection of AA in canned fruit juice. The NED acts as a linker to improve the stability of the polyaniline/MWCNT composite in neutral pH. The electrochemical sensor showed AA oxidation peak at low potential, –15 mV vs Ag/AgCl in pH 7 phosphate buffer solution. The Au/MWCNT@PANI-NED was characterized by cyclic voltammetry, Raman, FT-IR and UV-Vis spectroscopy techniques. Under optimal amperometric i–t condition, Au/MWCNT@PANI-NED showed AA calibration plot in a window 200–2000 µM with a current sensitivity of 13.45 nA µM–1. A canned fruit juice real sample was successfully analyzed with recovery value ~100%