Carbon Paste Composite with Co₃O₄ as a New Electrochemical Sensor for the Detection of Allura Red by Reduction

Abstract

The detection of Allura red (AR) by electrochemical reduction using a different electrode from the conventional mercury electrode is presented. A carbon paste with cobalt (II, III) oxide composite electrode (CoOx/CPE) is reported for the first time for the detection of AR. Moreover, others dyes such as tartrazine (TZ), sunset yellow (SY), amaranth (AM), Ponceaut 4‐R (P‐4R), and Sudan (SD) as well as pharmaceutical agents such as paracetamol (PMC) that are present in samples that contained AR did not show a reduced signal between 0.0 and −0.3 V, which is the potential range where AR reduction was observed. The surface electroactivity was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The presence of CoOX increased the cathodic peak current for AR by more than 50 % and 65 % via CV and square wave voltammetry (SWV), respectively, compared with an unmodified carbon paste electrode. Under the optimal parameters, (pH=3.0, accumulation time (tACC)=60 s and accumulation potential (EACC)=0.50 V), the detection limit for AR was 0.05 μmol L−1. The new sensor was sensitive and stable for the detection of AR. Moreover, it was easily manufactured and very convenient for food samples such as soft and isotonic drinks as well as chili sauce.

Sensitive and Profitable Electrochemical Detection of Uric Acid in the Presence of Dopamine with a Novel Carbon Paste Electrode Decorated with a Copper(II) Complex

“…These results indicate that the charge transfer rate was faster, due to the presence of metallic complex in the electrode. Similar results have been reported for CPE decorated with other metal ions, such as Co and La, where the presence of the metal ions did not change the potential value considerably, but the anodic and cathodic peak currents were increased [28,29]. The EDS image of the Cu C /CPE microstructure (Figure 1C) shows the presence of C as well as N, Cu and Cl.…”

A New Electrochemical Method to Detect Sunset Yellow, Tartrazine and Thiomersal in a Pharmaceutical Dose Using a Carbon Paste Electrode Decorated with Molybdenum Oxide

“…Recently, reports of electrodes modified with metal oxides have increased. Some reports of modified electrodes used cobalt oxide for detecting H 2 O 2 , As(III) and allura red [1][2][3], ruthenium oxide for detecting carbohydrates [4], nickel oxide for detecting glucose [5], zinc oxide for detecting hydrazine [6,7], neodymium oxide for detecting dopamine, sunset yellow and tartrazine [8,9] and lanthanide oxide for detecting thiomersal [10]. In these reports, several characteristics are observed that confirm the electroactive properties of these substances with the modified electrodes.…”

“…On the other hand, some of the most notable advantages of MoO 2 and other metals oxides, that justify the use in the modification of electrodes are; low toxicity, high chemical and thermal stability and a high dielectric constant [24]. Moreover, the currents increase considerably, possibly, electrostatic interactions between the metal ion and the analyte occur with an increase in the surface area [14,25]. Therefore, there is evidence of the great activity of metal ion oxides in the preparation of low-cost electrodes.…”

Titania/Electro-Reduced Graphene Oxide Nanohybrid as an Efficient Electrochemical Sensor for the Determination of Allura Red

“…To address the above-mentioned issues, much effort has been made to develop novel modified electrodes that are capable of efficiently detecting Allura Red based on the oxidation signals. Novel electrochemical sensors based on multiwalled carbon nanotube (MWCNT) [28,29], ionic liquids [30], cobalt oxide [31], and cobalt complex [32] modified electrodes have shown great potentials on the detection of Allura Red, due to their excellent accumulation efficiency and large specific surface area. For example, MWCNT/GCE showed a wide linear response range of 496-4468 µg/L, and it was applied to the analysis of commercial isotonic sports drinks with satisfactory results [28].…”