A Novel Electrochemical Nanosensor for the Simultaneous Sensing of Two Toxic Food Dyes

Engineered Nanomaterial Coatings for Food Packaging: Design, Manufacturing, Regulatory, and Sustainability Implications

The food industry is one of the most regulated businesses in the world and follows strict internal and regulated requirements to ensure product reliability and safety. In particular, the industry must ensure that biological, chemical, and physical hazards are controlled from the production and distribution of raw materials to the consumption of the finished product. In the United States, the FDA regulates the efficacy and safety of food ingredients and packaging. Traditional packaging materials such as paper, aluminum, plastic, and biodegradable compostable materials have gradually evolved. Coatings made with nanotechnology promise to radically improve the performance of food packaging materials, as their excellent properties improve the appearance, taste, texture, and shelf life of food. This review article highlights the role of nanomaterials in designing and manufacturing anti-fouling and antimicrobial coatings for the food packaging industry. The use of nanotechnology coatings as protective films and sensors to indicate food quality levels is discussed. In addition, their assessment of regulatory and environmental sustainability is developed. This review provides a comprehensive perspective on nanotechnology coatings that can ensure high-quality nutrition at all stages of the food chain, including food packaging systems for humanitarian purposes.

Recent advancements in nanomaterial based optical detection of food additives: a review

Food additives have become a critical component in the food industry. They are employed as preservatives to decelerate the negative effects of environmental and microbial factors on food quality. Currently, food additives are used for a variety of purposes, including colorants, flavor enhancers, nutritional supplements, etc., owing to improvements in the food industry. Since the usage of food additives has increased dramatically, the efficient monitoring of their acceptable levels in food products is quite necessary to mitigate the problems associated with their inappropriate use. The traditional methods used for detecting food additives are generally based on standard spectroscopic and chromatographic techniques. However, these analytical techniques are limited by their high instrumentation cost and time-consuming procedures. The emerging field of nanotechnology has enabled the development of highly sensitive and specific sensors to analyze food additives in a rapid manner. The current article emphasizes the need to detect various food additives owing to their potential negative effects on humans, animals, and the environment. In this article, the role of nanomaterials in the optical sensing of food additives has been discussed owing to their high accuracy, ease-of-use, and excellent sensitivity. The applications of nanosensors for the detection of various food additives have been elaborated with examples. The current article will assist policymakers in developing new rules and regulations to mitigate the adverse effects of toxic food additives on humans and the environment. In addition, the prospects of nanosensors for the optical detection of food additives at a commercial scale have been discussed to combat their irrational use in the food industry.

A highly efficient NiCo2O4 decorated g-C3N4 nanocomposite for screen-printed carbon electrode based electrochemical sensing and adsorptive removal of fast green dye

Herein, we demonstrate the preparation and application of NiCo2O4 decorated over a g-C3N4-based novel nanocomposite (NiCo2O4@g-C3N4). The prepared material was well characterized through several physicochemical techniques, including FT-IR, XRD, SEM, and TEM. The electrochemical characterizations via electrochemical impedance spectroscopy show the low electron transfer resistance of NiCo2O4@g-C3N4 owing to the successful incorporation of NiCo2O4 nanoparticles on the sheets of g-C3N4. NiCo2O4@g-C3N4 nanocomposite was employed in the fabrication of a screen-printed carbon electrode-based innovative electrochemical sensing platform and the adsorptive removal of a food dye, i.e., fast green FCF dye (FGD). The electrochemical oxidation of FGD at the developed NiCo2O4@g-C3N4 nanocomposite modified screen-printed carbon electrode (NiCo2O4@g-C3N4/SPCE) was observed at an oxidation potential of 0.65 V. A wide dual calibration range for electrochemical determination of FGD was successfully established at the prepared sensing platform, showing an excellent LOD of 0.13 µM and sensitivity of 0.6912 µA.µM-1.cm-2 through differential pulse voltammetry. Further, adsorbent dose, pH, contact time, and temperature were optimized to study the adsorption phenomena. The adsorption thermodynamics, isotherm, and kinetics were also investigated for efficient removal of FGD at NiCo2O4@g-C3N4-based adsorbents. The adsorption phenomenon of FGD on NiCo2O4@g-C3N4 was best fitted (R2 = 0.99) with the Langmuir and Henry model, and the corresponding value of Langmuir adsorption efficiency (qm) was 3.72 mg/g for the removal of FGD. The reaction kinetics for adsorption phenomenon were observed to be pseudo-second order. The sensitive analysis of FGD in a real sample was also studied.

Photoelectrocatalytic Detection and Degradation Studies of a Hazardous Textile Dye Safranin T

Herein, we report an electrochemical scaffold consisting of functionalized multiwalled carbon nanotubes (COOH-fMWCNTs) and iron-doped zinc oxide nanoparticles (Fe-ZnO) for the detection of a hazardous textile dye safranin T (ST) and monitoring of its photocatalytic degradation. Prior to the detection and degradation analysis, Fe-ZnO NPs were synthesized by the sol-gel method and characterized by a number of structural and morphological techniques. The carboxyl moiety of COOH-fMWCNTs possessing a strong affinity for the amino functionality of ST led to significant enhancement of the current response at the designed electrochemical platform, whereas the electrocatalytic role, surface area enhancement, and the provision of binding sites of Fe-ZnO led to a further increase in the peak current intensity of ST. Electrochemical impedance spectroscopy showed that the sensing scaffold made of the glassy carbon electrode modified with COOH-fMWCNTs and Fe-ZnO efficiently transfers charge between the transducer and the redox probe. Under optimized conditions, the developed sensor showed a 2.3 nM limit of detection for ST. Moreover, recovery experiments and anti-interference tests qualified the sensing platform for practical applications. The dye was photocatalytically degraded using Fe-ZnO NPs up to 99% in 60 min with a rate constant of 0.068 min-1. The designed sensor was used to probe the degradation kinetics of the target dye, and the results were found consistent with the findings obtained from electronic absorption method. To the best of our knowledge, the present work is the first approach for the efficient detection and almost absolute degradation of ST.

Photocatalytic Degradation of Food and Juices Dyes via Photocatalytic Nanomaterials Synthesized through Green Synthetic Route: A Systematic Review

The unavailability of non-poisonous and hygienic food substances is the most challenging issue of the modern era. The uncontrolled usage of toxic colorant moieties in cosmetics and food manufacturing units leads to major threats to human life. The selection of environmentally benign approaches for the removal of these toxic dyes has gained the utmost attention from researchers in recent decades. This review article's main aim is the focus on the application of green-synthesized nanoparticles (NPs) for the photocatalytic degradation of toxic food dyes. The use of synthetic dyes in the food industry is a growing concern due to their harmful effects on human health and the environment. In recent years, photocatalytic degradation has emerged as an effective and eco-friendly method for the removal of these dyes from wastewater. This review discusses the various types of green-synthesized NPs that have been used for photocatalytic degradation (without the production of any secondary pollutant), including metal and metal oxide NPs. It also highlights the synthesis methods, characterization techniques, and photocatalytic efficiency of these NPs. Furthermore, the review explores the mechanisms involved in the photocatalytic degradation of toxic food dyes using green-synthesized NPs. Different factors that responsible for the photodegradation, are also highlighted. Advantages and disadvantages, as well as economic cost, are also discussed briefly. This review will be advantageous for the readers because it covers all aspects of dyes photodegradation. The future feature and limitations are also part of this review article. Overall, this review provides valuable insights into the potential of green-synthesized NPs as a promising alternative for the removal of toxic food dyes from wastewater.

Appraising the electrocatalytic performance of beta-cyclodextrin embellished supramolecular recognition system for pernicious food colorants

The current research presents the evaluation of supramolecular proficiency of the designed platform for electrocatalytic determination of pernicious food colorants, amaranth and fast green. The approach involving surface modification of glassy carbon electrode with beta cyclodextrin decorated strontium ferrite reduced graphene oxide nanocomposite (SFrGO-βCD) to ensure fast and reversible electro-oxidation of hydroxyl groups of the colorant molecules. The synergy between SF and rGO facilitated the sensor with enhanced surface area and conductivity through faradic redox reaction. Tremendous decrease in the obtained values of peak separation potential and impedance as manifested in CV and EIS analysis, enabled by electrostatic interactions between surface functionalities of rGO and βCD has resulted in the significant augmentation of sensitivity. The value of charge transfer coefficient, number of electrons involved, nature of electron transport process at electrode electrolyte interface during the analysis of electrochemical detection were explored through CV experiments. Food samples analysis (without spiking) utilizing screen printed electrode manifested the sensor as portable device for real time monitoring. Outstanding detection limit (0.022 nM for amaranth and 0.051 nM for fast green), excellent regenerability (Relative standard deviation less than 3%) and apparent recovery rate (above 90%) of the modified electrode presented a colossal potential for the development of sustainable and commercially competitive electrochemical sensor in food sector.

In situ synthesis of polythiophene encapsulated 2D hexagonal boron nitride nanocomposite based electrochemical transducer for detection of 5-fluorouracil with high selectivity

It is difficult for the scientific community to develop a nonenzymatic sensing platform for extremely sensitive and selective detection of specific biomolecules, antibiotics, food adulterants, heavy metals, etc. One of the most significant chemotherapy drugs, 5-fluorouracil (5-Fu), which is used to treat solid malignancies, has a fluorine atom in the fifth position of the uracil molecule. Recognizing the secure and effective dosing of drugs for chemotherapy continues to be a critical concern in cancer disease management. The maintenance of the optimal 5-Fu concentration is dependent on the presence of 5-Fu in biofluids. Herein we reported a conducting polymer encapsulated 2D material, PTh/h-BN for the efficient electrochemical detection of anticancer drug 5-Fu. Furthermore, the synthesized PTh/h-BN nanocomposite was confirmed by the High-Resolution Transmission Electron Microscope (HR-TEM), High-Resolution Scanning Electron Microscope (HR-SEM), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FT-IR). The electrical resistance of PTh/h-BN modified GCE and its sensing performance towards 5-Fu were tested using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) studies respectively. The analytical performance of our proposed catalyst was tested using Differential Pulse Voltammetry (DPV), and the amperometry (i-t curve) method. From the results, our proposed PTh/h-BN nanocomposite-modified GCE shows enhanced sensing performance due to higher redox peak currents, large active surface area, and high electrical conductivity. Moreover, the nanohybrid shows enhanced sensing performances with quick response time, wide linear range, the lowest limit of detection, high sensitivity, and high selectivity in the presence of various interferents. Finally, the practical applicability of the proposed sensor was tested with real-world samples with very good recovery percentages.

Detection and Degradation Studies of Nile Blue Sulphate Using Electrochemical and UV-Vis Spectroscopic Techniques

An efficient and reliable electrochemical sensing platform based on COOH-fMWCNTs modified GCE (COOH-fMWCNTs/GCE) was designed for the detection of nanomolar concentration of Nile Blue Sulphate (NBS). In comparison to the bare GCE, the electrochemical sensing scaffold considerably enhanced the peak current response of NBS dye as confirmed from the results of voltammetric investigations. The electrochemical approach of detecting NBS in the droplet of its solution dried over the surface of modified electrode validated, the role of modifier in enhancing the sensing response. Under optimized conditions, the designed electrochemical platform demonstrated a wide linearity range (0.03–10 μM) for NBS, with LOD of 1.21 nM. Moreover, COOH-fMWCNTs/GCE was found reproducible and stable as confirmed by repeatability and inter-day durability tests. The selectivity of the designed sensing matrix was ensured by anti-interference tests. The photocatalytic degradation of NBS dye was carried out by using TiO2 nanoparticles as photocatalyst in the presence of H2O2. UV-visible spectroscopic studies revealed 95% photocatalytic degradation of NBS following a pseudo-first-order kinetics with a rate constant of 0.028 min−1. These findings were supported electrochemically by monitoring the photocatalytically degraded dye at the designed sensing platform. The color variation and final decolorization of the selected dye in water served as a visual indicator of the degradation process. To conclude, the designed sensing platform immobilized with COOH-fMWCNTs imparted improved selectivity and sensitivity to detect and to, monitor the photocatalytic degradation of NBS.

A designed miniature sensor for the trace level detection and degradation studies of the toxic dye Rhodamine B

The presence of organic pollutants in water and food samples is a risk for the environment. To avoid this hazard a variety of analytical tools are used for the detection of toxic organic contaminants. Herein we present a selective and sensitive electrochemical sensor based on amino group functionalized multi walled carbon nanotubes and carboxylic group functionalized multi walled carbon nanotubes (HOOC-fMWCNTs/NH2-fMWCNTs) as modifiers of the glassy carbon electrode for the detection of a toxic dye, Rhodamine B. The sensing ability of the designed sensor was examined by electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry. The synergistic effect of HOOC-fMWCNTs and NH2-fMWCNTs (layer by layer) led to enhanced electrocatalytic activity of the modified electrode surface for Rhodamine B detection. Under optimized conditions, the graph between concentration and peak current followed a linear trend in the concentration range of 0.1 nM to 0.05 μM. The limits of detection and quantification were found to be 57.4 pM and 191.3 pM respectively. The designed sensor was also used for probing the degradation of Rhodamine B. Sodium borohydride was found to degrade Rhodamine B in neutral media under ambient conditions. The kinetics of degradation followed first order kinetics. Rhodamine B degraded to the extent of more than 80% as revealed by electrochemical and spectrophotometric techniques. The developed method is promising for the treatment of dye contaminated wastewater. Moreover, it uses only a microliter volume of the sample for analysis.

Advancement in electrochemical strategies for quantification of Brown HT and Carmoisine (Acid Red 14) Drom Azo Dyestuff class

Brown HT and carmoisine, which are the most used dyestuffs in pharmaceuticals, textiles, cosmetics and foods, are important components of the Azo family. Although the Azo group is not toxic or carcinogenic under normal conditions, these dyestuffs require great care due to the reduction of the Azo functional group to amines. In particular, fast, reliable, easy, on-site and precise determinations of these substances are extremely necessary and important. In this review, the properties, applications, and electrochemical determinations of brown HT and carmoisine, which are used as synthetic food colorants, are discussed in detail. Up to now, sensor types, detection limits (LOD and LOQ), and analytical applications in the developed electrochemical strategies for both substances were compared. In addition, the validation parameters such as the variety of the sensors, sensitivity, selectivity and electrochemical technique in these studies were clarified one by one. While the electrochemical techniques recommended for brown HT were mostly used for the removal of dyestuff, for carmoisine they included fully quantitative centered studies. The percentiles of voltammetric techniques, which are the most widely used among these electroanalytical methods, were determined. The benefits of a robust electrochemical strategy for the determination of both food colors are summed up in this review. Finally, the brown HT and carmoisine suggestions for future perspectives in electrochemical strategy are given according to all their applications.

Design, Elaboration, and Characterization of an Immunosensor for the Detection of a Fungal Toxin in Foodstuff Analyses

This work describes the complete elaboration of an immunosensor for the detection of the fungal B1 aflatoxin (AFB1). In a first step, a system made of three screen-printed electrodes (SPEs) was manufactured using gold, silver/silver chloride, and carbon pastes. Raman spectroscopy showed that the thermal treatment applied to the electrodes enabled a strong decrease in the amount of undesirable organic molecules for each paste. Atomic Force Microscopy was also used to reveal the morphology of the electrode surfaces. In a second step, an autonomous and cheap electronic system was designed for the control of the sensor and electrochemical measurements, showing current variations significantly higher than those observed with a commercial system. In a last step, the gold working electrode of this system was functionalized by a simple self-assembly method, optimized in a previous work, with a molecular architecture including an antibody recognizing specifically AFB1. The complete device was finally realized by combining the SPEs and the electronic platform. The resulting setup was able to detect AFB1 toxin in a buffer with an LOD of about 50 fg/mL. It was then applied to the detection of AFB1 in rice milk, a more realistic medium comparable with those met in an agrifood context. The electrochemical detection of AFB1 was possible in a range of concentration between 0.5 pg/mL and 2.5 pg/mL, with the sensor behaving linearly in this range.