Simultaneous determination of tartrazine, sunset yellow and allura red in foods using a new cobalt-decorated carbon paste electrode

Recent advances in electrochemical detection of common azo dyes

PURPOSE

Food forensics is an emerging field and the initial part of this review showcases the toxic effects and the instrumental methods applied for the detection of the most commonly used azo dyes. Electrochemical detection has a lot of advantages and hence the significance of the most important techniques used in the electrochemical detection is discussed. The major part of this review highlights the surface modified electrodes, utilized for the detection of the most important azo dyes to achieve low detection limit (LOD).

METHODS

A thorough literature study was conducted using scopus, science direct and other scientific databases using specific keywords such as toxic azo dyes, electrochemical detection, modified electrodes, LOD etc. The recent references in this field have been included.

RESULTS

From the published literature, it is observed that with the growing interests in the field of electrochemical techniques, a lot of importance have been given in the area of modifying the working electrodes. The results unambiguously show that the modified electrodes outperform bare electrodes and offer a lower LOD value.

CONCLUSION

According to the literature reports it can be concluded that, compared to other detection methods, electrochemical techniques are much dependable and reproducible. The fabrication of the electrode material with the appropriate modifications is the main factor that influences the sensitivity. Electrochemical sensors can be designed to be more sensitive, more reliable, and less expensive. These sensors can be effectively used by toxicologists to detect trace amounts of harmful dyes in food samples.

An Innovative Selective Fluorescence Sensor for Quantification of Hazardous Food Colorant Allura Red in Beverages Using Nitrogen-Doped Carbon Quantum Dots

An innovative simple, sensitive, and selective method has been developed and validated for quantification of hazardous Allura red (AR, E129) dye in beverages. Allura red (AR) is a synthetic dye that is commonly used in the food industry to give foods a bright and appealing color. The method is based on microwave-assistant nitrogen-doped carbon quantum dots (N@CQDs) from a very cheap source with a high quantum yield equal to (36.60%). The mechanism of the reaction is based on an ion-pair association complex between AR and nitrogen-doped carbon quantum dots (N@CQDs) at pH 3.2. The reaction between AR and N@CQDs led to a quenching effect of the fluorescence intensity of N@CQDs at 445 nm after excitation at 350 nm. Moreover, the quantum method's linearity covered the range between 0.07 and 10.0 µg mL- 1 with a regression coefficient is 0.9992. The presented work has been validated by ICH criteria. High-resolution transmission electron microscopy (HR-TEM), X-ray photon spectroscopy (XPS), Zeta potential measurements, fluorescence, UV-VIS, and FTIR spectroscopy have all been used to fully characterize of the N@CQDs. The N@CQDs were successfully utilized in different applications (beverages) with high accuracy.

Voltammetric determination of tryptophan at graphitic carbon nitride modified carbon paste electrode

Herein, we reported carbon paste electrode modified with graphitic carbon nitride (g-C3N4-CPE) to determine of tryptophan (Trp) using voltametric techniques. Various spectroscopic and electrochemical techniques were used to characterize the as-synthesized g-C3N4 and the assembled electrodes. The transfer coefficient, rate constant and the diffusion coefficient of Trp in this system were found to be 0.28, 1.9 × 104 M-1s-1 and 3.2 × 10-5 cm2s-1, respectively. The linear range was obtained for the detection of Trp using LSV is from 0.1 μM to 120 μM at pH 5. The limit of detection (LOD) (3σ/m) was 0.085 μM. The demonstrated modified CPE was also effectively used for the detection of Trp in milk with percentage recovery of 98 %-105.2 %. Furthermore, the modified CPE exhibited good repeatability, reproducibility and appropriate selectivity.

Screen-printing of core-shell Mn3O4@C nanocubes based sensing microchip performing ultrasensitive recognition of allura red

Allura red (AR) is a member of azo dyes is commonly used as an additive in foods and soft drinks. However, due to the special harm of the azo structure to the human body, the dosage control of AR becomes particularly necessary. The present detection methods are time-consuming, expensive and complicated. In order to address the above issues, a core-shell nanocubes constructed sensor has been developed to determine the ultrawide detection range and selective recognition of AR with a long-term reusability. The core-shell architecture is composed of carbon material of 12.64 nm thickness covering 600 nm Mn3O4 nanocube. This nanocomposite combines the advantages of Mn3O4@C, possessing high electrocatalysis and chemical stability. As confirmed in using sports drinks as real samples, the as-prepared AR sensor exhibites excellent selectivity with an ultra-wide linear range from 0.1 to 1748.4 μM, and meanwhile, this sensor can also meet the requirements of remarkable anti-interference and reusability over 30 days.

An electrochemical sensor based on hierarchical nickel oxide nanostructures doped with indium ions for voltammetric simultaneous determination of sunset yellow and tartrazine colorants in soft drink powders

The current study was designed to develop a single-step and simple approach to effectively fabricate three-dimensional raspberry-like In³⁺/NiO hierarchical nanostructures (In³⁺/NiO RLHNSs) as a modifier, which was subsequently characterized by the techniques of X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and field emission scanning electron microscopy (FE-SEM). The new prepared nano-modifier was practically used to co-detect electrochemically sunset yellow and tartrazine dyes. Potent sensitivity and acceptable selectivity were obtained for the produced In³⁺/NiO RLHNSs to co-detect both the food colorants, thus providing oxidation peaks in differential pulse voltammetry (DPV) with a peak potential separation of ca. 190 mV. The results showed a 5.14-fold and 8.07-fold increase in the electrochemical response of our modified electrode to sunset yellow and tartrazine, respectively, compared to the control (the unmodified electrode). Limits of detection of 2.7 and 3.1 nM were calculated for sunset yellow and tartrazine, respectively. The results from the interaction of common food additives showed satisfactory outcomes for the application of this method in determining sunset yellow and tartrazine in several beverage specimens. Other useful documentation was obtained for the production of portable food additive sensors.

A Short Review on Electrochemical Sensing of Commercial Dyes in Real Samples Using Carbon Paste Electrodes

Synthetic dyes are commonly used in food products like soft drinks, vegetable sauces, jellies, etc. Most artificial dyes can cause cancer, therefore it is very important to develop sensors to detect them in food samples. Voltammetric methods with carbon paste electrodes (CPEs) are promising for this purpose. However, modification of CPEs is necessary to detect the commercial dyes in food samples in the presence of interferents. In the current review, we have discussed the different previous research in which detection of dyes is performed in real samples with good detection limits. The current review will be helpful for readers who are interested in developing low-cost electrodes for the effective determination of dyes in commercial products like soft drinks and vegetable sauces.

Electrochemical determination of paracetamol in a pharmaceutical dose by adsorptive voltammetry with a carbon paste/La2O3 microcomposite

This paper presents a new application for microcomposites based on carbon paste (CP) and La2O3 (LaOX). This simple and versatile microcomposite (LaOX/CPE) was applied toward the determination of paracetamol (PCM) through proton oxidation by square wave adsorptive voltammetry (SWAdV). The anodic peak current for PCM increased by nearly 70.0% compared with an unmodified CP, and the detection limit was 0.020 μmol L-1. The relative standard deviations (RSDs) were 1.0% (n = 7). The accuracy of the new method was evaluated with tap water spiked with known quantities of PCM, while ascorbic acid, caffeine, and acetylsalicylic acid were used for interference studies. Finally, the usefulness of the microcomposite was shown to have acceptable results when applied to detect and quantify PCM in various forms of a pharmaceutical dose, such as solid tablets, fruit-flavored powders for colds and syrups for children.

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

Titania/electro-reduced graphene oxide nanohybrids (TiO2/ErGO) were synthesized by the hydrolysis of titanium sulfate in graphene oxide suspension and in situ electrochemical reduction. It provides a facile and efficient method to obtain nanohybrids with TiO2 nanoparticles (TiO2 NPs) uniformly coated by graphene nanoflakes. TiO2/ErGO nanohybrids were characterized by transmission electron microscopy, X-ray diffraction, cyclic voltammogram, and electrochemical impedance spectroscopy in detail. Compared with pure ErGO and TiO2 NPs, TiO2/ErGO nanohybrids greatly enhanced the electrocatalytic activity and voltammetric response of Allura Red. In the concentration range of 0.5-5.0 μM, the anodic peak currents of Allura Red were linearly correlated to their concentrations. However, the linear relationship was changed to the semi-logarithmic relationship at a higher concentration region (5.0-800 μM). The detection limit (LOD) was 0.05 μM at a signal-to-noise ratio of 3. The superior sensing performances of the proposed sensor can be ascribed to the synergistic effect between TiO2 NPs and ErGO, which provides a favorable microenvironment for the electrochemical oxidation of Allura Red. The proposed TiO2/ErGO/GCE showed good reproducibility and stability both in determination and in storage, and it can accurately detect the concentration of Allura Red in milk drinks, providing an efficient platform for the sensitive determination of Allura Red with high reliability, simplicity, and rapidness.

Synthetic Food Dyes – Some Aspects Of Use And Methods Of Determination

Color is one of the key ingredients for increasing the appetizing of food, so food dyes have become firmly established in food production technologies. However, with the acquisition of toxicity data of synthetic food dyes (SFD), there were restrictions and standards for their content in food have emerged. Numerous papers published in recent years demonstrate the importance of the problem of the use and definition of SFD. The review contains over 180 literary references in the field of usage and methods of determination of synthetic food dyes, among them regulatory documents (regulations), official internet resources of international and Ukrainian organizations, review articles and original works. Varieties of chromatography, enzyme-linked immunoassay, optical and electrochemical methods are used to identify and determine SFD. Special attention was paid to voltammetry (VA) as a method that is cheaper than chromatography and completely satisfies selectivity, sensitivity, reliability requirements and is compatible with the concept of green analytical chemistry, as it doesn't need organic solvents. Moreover, single sweep voltammetry can be considered as a screening method with low limits of determination and rapid respons