A glassy carbon electrode modified with a new simple nanocomposite film based on multiwall carbon nanotubes and zein nanoparticle for simultaneous determination of ascorbic acid, dopamine and uric acid

Zein is the major storage protein in corn or maize, has attracted attention because of its potential applications as an industrial biopolymer. Zein protein can form composites or conjugates with other compounds such as nanomaterials and also in encapsulation processes. Therefore, in recent years, several research groups have reported the use of nanoparticles in different research areas such as drug delivery, food science, pharmaceutics, and biomedicine [1]. Carbon nanotubes (CNTs) have been considered as an important class of nanomaterials with excellent mechanical, electrical and chemical properties since they have been discovered. These unique properties make them extremely attractive for fabricating electrochemical sensors because of the ability of CNTs to facilitatethe electron transfer reactions [2]. However, no works have been reported about the use of zein/multiwall carbon nanotubes nanocomposite for glassy carbon electrode modification for electroanalytical applications. For a mixture containing ascorbic acid (AA), dopamine (DA) and uric acid (UA), the three compounds can well separate from each other at the scan rate of 100 mV s−1 with a potential difference of 250 mV and 160 mV for the oxidation peak potentials of AA–DA and DA–UA, respectively, which was large enough to simultaneous determine AA, DA and UA. The catalytic peak current linearly depended on the AA, DA and UA concentrations in the range of 8.55–812 μM, 7.85–824 μM and 0.33–73.3 μM, respectively. The detection limits for AA, DA and UA were 2.11, 2.05 and 0.056, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of AA, DA, and UA in human serum and urine samples.