Application of Multi‐walled Carbon Nanotube Modified Carbon Ionic Liquid Electrode for the Voltammetric Detection of Dopamine

Abstract

In this paper a carbon ionic liquid electrode (CILE) was fabricated by using ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) as the binder. Then a Nafion and multi‐walled carbon nanotubes (MWCNTs) composite material was further cast on the CILE surface to get a modified electrode denoted as Nafion‐MWCNTs/CILE. The fabricated electrode showed strong electrocatalytic ability to the oxidation of dopamine (DA) with a pair of well‐defined redox peaks appeared. Compared with other electrodes the redox peak currents increased with the decrease of the peak‐to‐peak separation (Δ Ep), and the result was attributed to the specific properties of MWCNTs and its interaction with imidazolium ion present on the CILE surface. The electrochemical parameters of DA on the Nafion‐MWCNTs/CILE were calculated with the electron transfer coefficient (α) as 0.433, the electron transfer number (n) as 1.1, the apparent heterogeneous electron transfer rate constant (ks) as 0.774 s−1 and the diffusion coefficient (D) as 3.05 × 10−5 cm2/s. Under the selected conditions the oxidation peak current was in linear with DA concentration from 1.0 × 10−5 to 6.0 × 10−4 mol/L with the detection limit as 6.75 × 10−6 mol/L (3σ)by differential pulse voltammetry. The proposed method showed good selectivity and was further applied to the DA injection samples determination with satisfactory results.

Electroanalytical Application of Amine‐grafted Attapulgite to the Sensitive Quantification of the Bioactive Compound Mangiferin

“…where n is the number of electrons transferred, F is the Faraday constant, A is the surface area of the electrode, D is the diffusion coefficient, C is the bulk concentration of the species, t is the potential pulse width, Q c is the capacitive or double layer charge and Q ads is the faradaic component due to the oxidation of adsorbed species .…”

Ionic Liquids with Various Constituent Ions To Optimize Non-Enzymatic Electrochemical Detection Properties of Graphene Electrodes

“…In addition, the detection limits (at a signal-to-noise ratio of 3) were measured to be 0.88, 068, 0.24, and 0.11 μM, respectively. It is worth noting that the exceptional detection limit of the graphene/EMI–SCN electrode is superior to most values reported in the literature − (see Table S1).…”

“…Some previous works utilized graphene/IL composite electrodes for the sensing of hydroquinone, ascorbic acid (AA), dopamine (DA), uric acid (UA), and DNA. , Many studies have found that IL incorporation enhances electrode-sensing performance. A short review of previous works in this field is provided in the Supporting Information (see Table S1). − …”

Fullerene/MWCNT/Nafion Modified Glassy Carbon Electrode for the Electrochemical Determination of Caffeine

“…A plot of logj pa vs logv (result not shown) was used to determine whether the oxidative behavior of CAF was due to diffusion or adsorption. The slope of 0.87 > 0.5 for a theoretical diffusion-controlled process allowed to conclude that a mixed behavior showing both adsorption and diffusion-controlled processes were involved [36]. When the scan rate increased, the anodic peak po-…”