Fullerene-MWCNT nanostructured-based electrochemical sensor for the detection of Vanillin as food additive

All-polysaccharide, self-healing, pH-sensitive, in situ-forming hydrogel of carboxymethyl chitosan and aldehyde-functionalized hydroxyethyl cellulose

In situ forming hydrogels are promising for biomedical applications, especially in drug delivery. The precursor solution can be injected at the target site, where it undergoes a sol-gel transition to afford a hydrogel. In this sense, the most significant characteristic of these hydrogels is fast gelation behavior after injection. This study describes an all-polysaccharide, rapidly in situ-forming hydrogel composed of carboxymethyl chitosan (CMCHT) and hydroxyethyl cellulose functionalized with aldehyde groups (HEC-Ald). The HEC-Ald was synthesized through acetal functionalization, followed by acid deprotection. This innovative approach avoids cleavage of pyran rings, as is inherent in the periodate oxidation approach, which is the most common method currently employed for adding aldehyde groups to polysaccharides. The resulting hydrogel exhibited fast stress relaxation, self-healing properties, and pH sensitivity, which allowed it to control the release of an encapsulated model drug in response to the medium pH. Based on the collected data, the HEC-Ald/CMCHT hydrogels show promise as pH-sensitive drug carriers.

Neodymium niobate nanospheres on functionalized carbon nanofibers: a nanoengineering approach for highly sensitive vanillin detection

Vanillin (VAN), the primary aroma compound in vanilla, contributes significantly to sensory delight; however, its unrestrained presence poses notable health risks. In response to the demanding concern regarding food safety, researchers have directed their efforts towards the detection of VAN, seeking sustainable strategies for contamination prevention. A groundbreaking solution has emerged in the form of a novel sensing platform, whose core lies on a finely tuned electrode, crafted through the incorporation of nano-sized NdNbO4 spheres onto carbon nanofibers (CNFs). This incorporation serves to augment the capabilities of a glassy carbon electrode (GCE), transforming it into a highly sensitive detector primed for vanillin detection. The NdNbO4/f-CNF nanocomposite embodies a paradigm of synergistic collaboration, wherein the nonlinear cumulative effects of synergism and quantum confinement impart exceptional performance characteristics. Notably, the sensor achieves a low detection limit of 6.3 nmol L-1, indicative of its remarkable sensitivity of 2.3 μA μ(mol L-1)-1 cm-2 and precision of 1.519 and 4.72%. Moreover, the sensor boasts a wide linear range spanning from 0.001 to 63.101 μmol L-1. These attributes, coupled with its discerning selectivity and robust stability, underscore its efficacy as a versatile tool for vanillin detection. Indeed, its successful deployment in monitoring food samples underscores its applicability across diverse culinary contexts, further cementing its status as a pivotal asset in safeguarding food quality and consumer well-being.

Conductive phthalocyanine-based porous organic polymer as sensing platform for rapid determination of vanillin

Vanillin (Van) is widely utilized in processed foods and medicines for its appealing scent and multiple therapeutic benefits. However, its overconsumption poses a risk to public health, making its quantification essential for ensuring food and medicine safety and quality. This study introduces a stable and conductive phthalocyanine-based porous organic polymer (NiPc-CC POP), synthesized through a straightforward electrophilic substitution of nickel tetra-amine phthalocyanine (NiTAPc) with cyanuric chloride (CC). Appropriate characterization techniques were employed to determine the morphologies and structures of the synthesized materials. Furthermore, the NiPc-CC POP was applied to devise a sensitive Van detection method. Leveraging the high electrocatalytic activity of NiPc-CC POP toward Van oxidation, a linear response of 0.15-32 μmol L-1 was achieved, along with an exceptional detection limit of 0.10 μmol L-1. The sensor demonstrated high selectivity and stability. Samples of human serum and tablets spiked with Van were analyzed, yielding satisfactory recoveries. Consequently, this work contributes to the advancement of sensitive detection platforms for Van at minimal concentrations.

Electrochemical determination of ethylvanillin based on LaV@GAC nanocomposite

Ethyl vanillin (EVA) is widely used as a flavor additive in foods, and sensitive monitoring of EVA is of great significance for food safety. In this paper, the biomass of gum arabic derived carbon (GAC) coated with lanthanum vanadate (LaV) was constructed for the EVA sensor based on the synergistic effects of the electrochemical catalytic ability of LaV, the enhanced electrical conductivity with the GAC coating and the oxygen-containing functional groups in LaV@GAC. The as-developed LaV@GAC sensor showed a remarkable linear range from 0.06 μM to 100 μM and a low detection limit (LOD) of 6.28 nM. The electrochemical oxidation of EVA is limited by a diffusion-controlled process involving 2 electrons and 2 protons. Moreover, the LaV@GAC sensor has good recoveries (94.5-103.05%) for the detection of EVA in real milk powder samples. The proposed LaV@GAC sensor has good repeatability, high stability, and great potential for sensitive detection of flavor additives in food.

Smart and sensitive nanomaterial-based electrochemical sensor for the determination of a poly (ADP-ribose) polymerase (PARP) inhibitor anticancer agent

In this research, we propose a novel approach for constructing a sensitive and selective electrochemical sensor utilizing high-quality multi-walled carbon nanotubes functionalized with amino groups (MWCNT-NH2) for the detection of Talazoparib (TLZ), a poly (ADP-ribose) polymerase (PARP) enzyme inhibitor, in real samples. The MWCNT-NH2-based sensor exhibited remarkable performance characteristics, including excellent repeatability, reproducibility, and high selectivity against various interferences. Under optimized conditions, the sensor demonstrated a wide linear concentration range of 1.0-5.0 μM, with a low limit of detection (LOD) of 0.201 μM. Substantiated by rigorous analysis of pharmaceutical and biological matrices, our methodology emerges as a paragon of reliability, boasting recovery rates within the satisfactory bracket of 96.38-105.25%. The successful application of the MWCNT-NH2-based sensor in practical sample analysis highlights its potential for implementation in clinical and pharmaceutical settings. This research not only advances the application of MWCNT-NH2 in electrochemical sensing but also opens new avenues for the development and monitoring of innovative anticancer treatments. The insights gained from our study have far-reaching implications, pointing toward a future where precision and innovation converge to improve patient care and treatment outcomes.

Determination of vanillin in different food samples by using SMM/Au@ZIF-67 electrochemical sensor

Vanillin is a popular flavoring agent in many food products. Simple, fast, and reliable quantification of this compound is crucial for the food industry. In this work, we have developed a new electrochemical sensor for accurate detection of vanillin in various real samples. The composite electrode was made of sodium montmorillonite nanoclay (SMM) and gold nanoparticles modified ZIF-67 (Au@ZIF-67), in which SMM contributes to the large adsorption capacity of the analyte, ZIF-67 and SMM supply more sensing active sites, and gold nanoparticles provide high electrical conductivity. The sensing electrode was comprehensively characterized using Brunauer-Emmett-Teller, EDS, XRD, SEM, FTIR, and TEM, and its electrochemical behavior for determination of vanillin including the electrooxidation mechanism of vanillin and different parameters such as scan rate and pH value was investigated. The result revealed that a two electron-two proton process was involved in the electrooxidation of vanillin, which takes place more readily due to the lower potential on the surface of SMM/Au@ZIF-67/carbon paste electrode. The new composite electrode was also more sensitive to vanillin detection with an anodic peak current almost 2.6 times more than that of the bare electrode. A linear sensing concentration range was established between 1 and 1200 nM with a detection limit of 0. 3 nM and a limit of quantitation of 1 nM. For real samples, the sensor demonstrated excellent recovery rates and reliability that was comparable to the standard high-performance liquid chromatography method.

Nano solid phase micro membrane tip and electrochemical methods for vanillin analysis in chocolate samples

A polymer-based nanosensor and electrochemical methods were developed for the quantitative analysis of vanillin. The sample preparation was done using nano solid phase micro membrane tip extraction (NSPMMTE). A novel poly(phenylalanine)/TiO2/CPE sensor was built as the working electrode for the first time for the analysis of the vanillin substance. The electrochemical behavior and analytical performance of vanillin were examined in detail by cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) techniques via the oxidation process. The optimized modules of the DPSV technique that affected the vanillin peak current and peak potential were pH, pulse amplitude, step potential, and deposition time. The electroactive surface areas of bare CPE, TiO2/CPE, and poly(phenylalanine)/TiO2/CPE electrodes were found to be 0.135 cm2, 0.155 cm2, and 0.221 cm2, respectively. The limit of detection (LOD) was 32.6 μg/L in the 0.25-15.0 mg/L working range at pH 7.0. The selectivity of the proposed DPSV method for the determination of vanillin on the modified electrode was investigated in the presence of various organic and inorganic substances, and the determination of vanillin with high recovery was achieved with less than 5% relative error. The analytical application was applied in chocolate samples and the DPSV method was found highly efficient, reproducible, and selective.

A review on nanomaterial-based electrochemical sensors for determination of vanillin in food samples

Vanillin is an organic compound that not only acts as a flavoring and fragrance enhancer in some foods, but also can have antioxidant, anti-inflammatory, anti-cancer and anti-depressant effects. Nevertheless, its excessive use can be associated with side effects on human health. Consequently, there is a need to achieve a rapid vanillin determination approach to enhance food safety. The diversity and high sensitivity of analytical approaches has led researchers to use more advanced and efficient methods providing quantitative and qualitative outcomes in complex matrices. Among these, prominent attention has been drawn to electrochemical sensors for reasons such as reliability, simplicity, cost-effectiveness, portability, selectivity, and ease of operation, especially for the determination of vanillin. Nanomaterials are a good candidate for sensor construction due to their commendable physicochemical attributes. Some advanced nanostructures with promising platforms for high-sensitivity, highly selective, and long-lasting electrochemical sensors include graphene (Gr) and its derivatives, graphite carbon nitride (g-C₃N₄), carbon nanotubes (CNTs), metal nanoparticles, metal organic frameworks, carbon nanofibers (CNFs) and quantum dots. Study about sizes, dimensions, and morphologies of nanomaterials makes strong candidates for improving sensitivity or selectivity according to electrocatalytic abilities. The low LOD and wide linear range of samples demonstrated an excellent catalytic performance towards the vanillin oxidation. Some investigations have reported the synergistic effects like great conductivity of carbon nanomaterials which improved the electrocatalytic performance of nanocomposites which demonstrated the estimable sensitivity of nanomaterial-supported electrochemical sensors for determination of vanillin concentrations. The sensors which have reported have a commendable response to practical potential and evaluated in biscuit, pudding powder, chocolate, custard specimens and etc. sensitivity, stability, reproducibility and repeatability of suggested sensor were investigated. The present review article scrutinizes recent advances in the fabrication of nanomaterial-based electrochemical sensors to detect vanillin in various food matrices.

Second-order derivative of square-wave voltammetry for determination of vanillin at platinum electrode

A simple and sensitive method of data treatment by second-order derivative square wave voltammetry (SD-SWV) was developed for the determination of vanillin at a platinum electrode. It was shown that the irreversible oxidation reaction is controlled by the adsorption and occurs following a mechanism involving two electrons, similar to other phenolic derivatives. The experimental parameters of SWV which exert influence on vanillin determination, such as frequency, pulse amplitude, or step potential, were optimized. The calibration curve shows a linear range between 50 and 430 nM vanillin with a detection limit of about 19 nM (signal/noise = 3). The mathematical treatment of experimental data leads to enhances the sensitivity of the determination and was successfully used for the estimation of vanillin in commercial food products.

Electrochemical Sensing of Vanillin Based on Fluorine-Doped Reduced Graphene Oxide Decorated with Gold Nanoparticles

4-hydroxy-3-methoxybenzaldehyde (vanillin) is a biophenol compound that is relatively abundant in the world’s most popular flavoring ingredient, natural vanilla. As a powerful antioxidant chemical with beneficial antimicrobial properties, vanillin is not only used as a flavoring agent in food, beverages, perfumery, and pharmaceutical products, it may also be employed as a food-preserving agent, and to fight against yeast and molds. The widespread use of vanilla in major industries warrants the need to develop simple and cost-effective strategies for the quantitative determination of its major component, vanillin. Herein, we explore the applications of a selective and sensitive electrochemical sensor (Au electrodeposited on a fluorine-doped reduced-graphene-oxide-modified glassy-carbon electrode (Au/F-rGO/GCE)) for the detection of vanillin. The electrochemical performance and analytical capabilities of this novel electrochemical sensor were investigated using electrochemical techniques including cyclic voltammetry and differential pulse voltammetry. The excellent sensitivity, selectivity, and reproducibility of the proposed electrochemical sensor may be attributed to the high conductivity and surface area of the formed nanocomposite. The high performance of the sensor developed in the present study was further demonstrated with real-sample analysis.