Electrochemical Sensing of Nitrite Ions Using Modified Electrode by Poly 1,8-Diaminonaphthalene/Functionalized Multi-Walled Carbon Nanotubes

Abstract

A novel electrochemical sensor based on conducting polymer and multi-walled carbon nanotubes was reported for the detection of nitrite ions (NO2−). The hybrid material poly 1,8-Diaminonaphthalene (poly 1,8-DAN)/functionalized multi-walled carbon nanotubes (f-MWCNT) was prepared by using a simple electrochemical approach which is based on the deposition of functionalized multi-walled carbon nanotubes (f-MWCNT) on the surface of the electrode followed by the electropolymerization of 1,8-DAN using cyclic voltammetry. The morphology and the electro-catalytic properties of the obtained electrodes were investigated with Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) showing an improvement of the electronic transfer due to the synergic effect between the proprieties of poly 1,8-DAN and f-MWCNT. Under the optimum experimental conditions, the poly 1,8-DAN/f-MWCNT/CPE exhibited excellent electro-catalytic activity towards nitrite detection. The nitrite anodic peak potential decreased by 210 mV compared to the bare carbon paste electrode. The calibration plot of nitrite detection was linear in the range of concentration from 300 to 6500 nM with a low detection limit of 75 nM.

Electrochemical determination of vitamin B6 in pharmaceutical and energy drink samples

“…The band at 1447 cm −1 is assigned to C-H bending vibration of -CH2 [46]. The peak at 1380 cm −1 corresponds to O-H bending vibration [39]. The absorption band at about 1083 cm -1 can be ascribed to the C-O stretching vibrations of epoxy groups [46].…”

“…Absorption bands at 2918 and 2853 cm −1 are assigned to asymmetric and symmetric stretching vibrations of the C-H [46]. For F-MWCNT, a strong absorption band observed at 3445 cm −1 is attributed to OH stretching vibration of the ─COOH groups [39,46]. The absorption bands at 2927 and 2862 cm -1 are assigned to asymmetric and symmetric stretching vibrations of the C-H bond in CH2 of F-MWCNT, respectively [46].…”

“…Functionalization of MWCNTs was performed utilizing the acid oxidation method according to the procedure described in the literature with a minor modification [39]. Briefly, 500 mg of pristine MWCNTs was added to 100 mL of a concentrated solution of HNO3 and H2SO4 at a ratio 1:3 (v/v) in a 200 mL conical flask and heated at 80 °C with continuous starring for 5 h. The resulting mixture was diluted with 200 mL of distilled water and filtered.…”

“…A weak band at 1749 cm −1 is assigned to the stretching vibration of C=O of the carboxyl group [39].…”

Multiple Pulse Amperometry—An Antifouling Approach for Nitrite Determination Using Carbon Fiber Microelectrodes

“…The detection of nitrite through electrochemical methods can be accomplished by reduction or oxidation, although the detection based on the reduction process usually has a major interference from oxygen and nitrate. Then, the preferred detection method is through nitrite oxidation, alleviating problems with some common interferents [ 20 , 21 ].…”