Polyaniline/polyacrylic acid/multi-walled carbon nanotube modified electrodes for sensing ascorbic acid

Abstract

A multi-walled carbon nanotube composite electrode incorporating Polyaniline (PANI) and Polyacrylic acid (PAA) is presented by diffusing aniline and PAA into Nafion-MWCNTs membranes supported upon a platinum macrodisc electrode. Nafion is found to be an ideal medium for dispersion of MWCNTs and for the formation of a homogeneous composite. The composite has been characterized utilizing SEM, TEM, FT-IR and electrochemical techniques. Electrochemical characterization reveals that the redox activity of the composite is improved with the cumulative effect of MWCNTs and PAA as additives. The electroanalytical behavior of the composite is evaluated towards the sensing of ascorbic acid in the presence of dopamine and uric acid exhibiting a detection limit of 2.5 Â 10 À7 M.

Real Time In Vivo Measurement of Ascorbate in the Brain Using Carbon Nanotube‐Modified Microelectrodes

“…As shown in Figure 2A the anodic peak potential of AA determined by SWV was + 0.243 V vs. Ag/AgCl when using bare CFMs but, meaningfully, the peak was shifted negatively to À0.044 V in the case of Nafion/SWCNT-modified CFMs, indicating a strong electrocatalytic effect of CNTs. This observation is in agreement with previous works describing the electrocatalytic effect on the AA oxidation of MWCNTs-IL-Gel deposited on glassy carbon electrode [31], of MWCNTs/Nafion modified carbon fiber electrode [21] and of MWCNTs/ Nafion layer over platinum disc electrode on AA oxidation [23]. Noticeably, the electrocatalytic oxidation of DA at CFM/Nafion/SWCNT suffered a less pronounced negative shift than AA.…”

“…By using MWCNT modified microelectrodes [21] and carbon nanotube fiber microelectrodes [22], DA has been measured in the presence of AA. More recently, a polyaniline/polyacrylic/MWCNT modified Pt macrodisc electrode has been reported for measuring AA in the presence of DA and uric acid [23]. Furthermore, the simultaneous determination of AA, DA and uric acid by using a screen-printed graphene electrode [24] and chitosan-graphene modified electrodes has been reported [25].…”

Synthesis and characterization of MgO nanocrystals for biosensing applications

“…4e). [24][25][26][27][28][29][30][31], the prepared MgO nanobelt/PLL/GCE exhibited a wider linear range and a lower detection limit. These results indicated that the present MgO nanobelt/PLL/GCE has the potential to be applied effectively in biological systems.…”

Chemical sensors based on polymer composites with carbon nanotubes and graphene: the role of the polymer

“…Using the same approach, these authors developed a highly sensitive and rapid oxalate biosensor by covalently immobilizing oxalate oxidase enzyme onto an electrodeposited MWCNT-PANI composite via EDC/NHS chemistry. 161 Electropolymerization has also been employed by Tiwari et al 162 for the preparation of a composite electrode incorporating PANI and polyacrylic acid (PAA) deposited on a Naon-MWCNT membrane supported over a Pt electrode. Naon has hydrophobic and hydrophilic regions and can wrap around the hydrophobic nanotube surface, and hence it is found to be an ideal medium for MWCNT dispersion, enabling the formation of a homogeneous composite.…”

“…Many examples demonstrate the use of this approach in the specic electrochemical detection of relevant molecules. [158][159][160][161][162][163][164][165][166][167][168][169] For example, an electrode composed of MWCNTs and poly(3-methylthiophene), P3MT, was developed by Agüí et al…”