Simultaneous Determination of Ascorbic Acid, Acetaminophen, and Tryptophan by Square Wave Voltammetry Using N-(3,4-Dihydroxyphenethyl)-3,5-Dinitrobenzamide-Modified Carbon Nanotubes Paste Electrode

Highly Sensitive and Selective Detection of L-Tryptophan by ECL Using Boron-Doped Diamond Electrodes

L-tryptophan is an amino acid that is essential to the metabolism of humans. Therefore, there is a high interest for its detection in biological fluids including blood, urine, and saliva for medical studies, but also in food products. Towards this goal, we report on a new electrochemiluminescence (ECL) method for L-tryptophan detection involving the in situ production of hydrogen peroxide at the surface of boron-doped diamond (BDD) electrodes. We demonstrate that the ECL response efficiency is directly related to H2O2 production at the electrode surface and propose a mechanism for the ECL emission of L-tryptophan. After optimizing the analytical conditions, we show that the ECL response to L-tryptophan is directly linear with concentration in the range of 0.005 to 1 µM. We achieved a limit of detection of 0.4 nM and limit of quantification of 1.4 nM in phosphate buffer saline (PBS, pH 7.4). Good selectivity against other indolic compounds (serotonin, 3-methylindole, tryptamine, indole) potentially found in biological fluids was observed, thus making this approach highly promising for quantifying L-tryptophan in a broad range of aqueous matrices of interest.

Electrochemical sensor based on molecularly imprinted copolymer for selective and simultaneous determination of riboflavin, dopamine, and L-tryptophan

This research shows the exact detection of riboflavin (RF), dopamine (DA), and L-tryptophan (Trp) through molecularly imprinted polymer (MIP) based on the electropolymerization method. MIP was placed on the surface of the glassy carbon electrode (GCE) by electropolymerization of monomers such as catechol and para-aminophenol, in the presence of all three analytes. The introduced sensor was investigated using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR), and electrochemical methods, for example, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The MIP/GCE performs well in terms of selectivity, reproducibility, repeatability, and stability. This sensor revealed good linear ranges of 0.005-500 μM for RF, 0.05-500 μM for DA, and 0.1-250 μM for Trp with limits of detection (LOD) as 0.0016 μM, 0.016 μM, and 0.03 μM for RF, DA, and Trp, respectively. The modified GCE was successfully applied to detect RF, DA, and Trp in serum and milk samples with satisfactory results.

A novel atropine electrochemical sensor based on silver nano particle-coated Spirulina platensis multicellular blue-green microalga

In this work, Atropine as the anticholinergic drug was measured using the environmentally friendly sensor. In this regard, Self-cultivated Spirulina platensis with electroless silver was employed as a powder amplifier in carbon paste electrode modification. Also, 1-Hexyl-3 methylimidazolium Hexafluorophosphate (HMIM PF₆) ion liquid as a conductor binder was used in the suggested electrode construction. Atropine determination was investigated by voltammetry methods. According to voltammograms, the electrochemical behavior of atropine depends on pH, and pH 10.0 was used as the optimal condition. Moreover, the diffusion control process for the electro-oxidation of atropine was verified by the scan rate study, so the diffusion coefficient (D∼ 3.0136×10^-4cm²/sec) value was computed from the chronoamperometry study. Furthermore, responses of the fabricated sensor were linear in the concentration range from 0.01 to 800 μM, and the lowest detection limit of the Atropine determination was obtained at 5 nM. Moreover, the stability, reproducibility, and selectivity factors of the suggested sensor were confirmed by the results. Finally, the recovery percentages for atropine sulfate ampoule (94.48-101.58), and water (98.01-101.3) approve of the applicability of the proposed sensor to Atropine determination in real samples.

A bibliometric analysis of graphene in acetaminophen detection: Current status, development, and future directions

Acetaminophen is a widely used analgesic throughout the world. Detection of acetaminophen has particular value in pharmacy and clinics. Electrochemical sensors assembled with advanced materials are an effective method for the rapid detection of acetaminophen. Graphene-based carbon nanomaterials have been extensively investigated for potential analytical applications in the last decade. In this article, we selected papers containing both graphene and acetaminophen. Bibliometrics was used to analyze the relationships and trends among these papers. The results show that the topic has grown at a high rate since 2009. Among them, the detection of acetaminophen by an electrochemical sensor based on graphene is the most important direction. Graphene has moved from being a primary sensing material to a substrate for immobilization of other active ingredients. In addition, the degradation of acetaminophen using graphene-modified electrodes is also an important direction. We analyzed the research history and current status of this topic through bibliometrics. Authors, institutions, countries, and key literature were discussed. We also proposed perspectives for this topic.

A zinc oxide nanorods/molybdenum disulfide nanosheets hybrid as a sensitive and reusable electrochemical sensor for determination of anti-retroviral agent indinavir

This work aims to develop an electrochemical sensor for the reusable and selective detection of trace levels of indinavir (IDV) as an anti-retroviral drug by using zinc oxide nano-rods/molybdenum disulfide nanosheets on a screen-printed electrode (ZnO NRs/MoS₂ NSs/SPE). Quantitative IDV detection was achieved using differential pulse voltammetry (DPV). The assay specificity was illustrated using interfering species and exhibited high specificity toward the IDV. The developed displayed a wide dynamic range, from 0.01 to 0.66 and 0.66-7.88 μM in Britton-Robinson (B-R) buffer, with a 0.007 μM limit of detection. The fabricated ZnO NRs/MoS₂ NSs/SPE electrode exhibited high sensitivity, stability, good reproducibility, and repeatability towards the sensing of IDV. It turned out that the hybrid electrochemical sensor's sensing performance was remarkably improved due to the synergistic effect between MoS₂ NSs and ZnO NRs, where the former affords a large active surface area and quick electron transfer. The reported sensor provides a new alternative for electrochemical detection of IDV and could expand the applications of metal nanoparticles in emerging technologies for monitoring drugs in real samples.

Electrochemical determination of L-tryptophan in food samples on graphite electrode prepared from waste batteries

One of the goals of this research was to develop an electrochemical sensor that had the ability to determine the target analyte and was both cheap and non-toxic. Another goal was to influence the reduction of electronic waste. In accordance with these, a graphite rod from zinc-carbon batteries was used to prepare an electrochemical sensor for the determination of L-tryptophan in Britton–Robinson buffer solution. Two electrochemical methods were used in the experimental research, differential pulse voltammetry and cyclic voltammetry. The effect of different parameters, including the pH value of supporting solution, scan rate, as well as the concentration of L-tryptophan on the current response, was studied. The pH value of Britton–Robinson buffer influenced the intensity of L-tryptophan oxidation peak, as well as the peak potential. The intensity of the current response was the highest at pH 4.0, while the peak potential value became lower as the pH increased, indicating that protons also participated in the redox reaction. Based on the obtained data, electrochemical oxidation of L-tryptophan at the graphite electrode was irreversible, two electron/two proton reaction. In addition, it was observed that the oxidation peak increased as the scan rate increased. According to the obtained electrochemical data, it was suggested that the oxidation of L-tryptophan was mixed controlled by adsorption and diffusion. The linear correlation between oxidation peak and L-tryptophan concentration was investigated in the range 5.0–150.0 µM and the obtained values of limit of detection and limit of quantification were 1.73 µM and 5.78 µM, respectively. Also, the prepared electrochemical sensor was successful in determination of target analyte in milk and apple juice samples.

Recent advantages in electrochemical monitoring for the analysis of amaranth and carminic acid food colors

This study provides a comprehensive review of the latest developments in the electrochemical impressions of the important dyestuffs including amaranth and carminic acid. Food colors are organic substances that have important effects on human health and food safety. While these substances do not pose a problem when used in the daily intake (ADI) amounts, they harm human health when consumed excessively. Amaranth and carminic acid are synthetic and natural food colors ingredients, respectively. Analysis of these substances in food, pharmaceutical, cosmetic and textile samples is extremely important because of their genotoxicity, cytostatic and cytotoxic effects. Electroanalytical methods, which have great advantages over traditional analytical methods, shed light on the scientific world. Electrochemical monitoring modules, which are fast, simple, accurate, reliable, and highly selective, are promising for the determination of both substances. Until now, amaranth and carminic acid food determinations have been carried out successfully with electrochemical monitoring techniques in many numbers in the literature. Voltammetric techniques are the most widely used among these electroanalytical methods. In particular, square wave and differential pulse voltammetric techniques, which have extraordinary properties, have been heavily preferred. Limits of detection (LOD) comparable to the standard analytical method have been achieved using these methods, which have very quick analysis durations, high precision and accuracy, do not require long preprocessing, and have great selectivity. In addition, more sensitive and selective analyses of amaranth and carminic acid in natural samples were carried out with numerous indicator electrodes. The merits of powerful electrochemical monitoring studies for the determination of both food colors during the last decade are presented in this study. Moreover, parameters such as analytical applications, detection limits, electrochemical methods, selectivity, working electrodes, and working ranges are summarized in detail.

Monitoring of atropine anticholinergic drug using voltammetric sensor amplified with NiO@Pt/SWCNTs and ionic liquid

In this work, the synergic impact of 1-ethyl-3-methylimidazolium methyl sulfate (EMMS) and NiO doped Pt decorated SWCNTs (NiO@Pt/SWCNTs) in carbon paste matrix was examined as an analytical tool for investigating electrochemical behavior of atropine. The voltammetric results revealed that NiO@Pt/SWCNTs/EMMS/CPE exhibited an excellent electrocatalytic activity towards redox reaction of atropine in aqueous solution pH = 10.0. The NiO@Pt/SWCNTs/EMMS/CPE offered the best electro-analytical conditions for monitoring of atropine in the concentration range of 4.0 nM-220 μM with an increase in oxidation current about 5.93 times. On the other hand, NiO@Pt/SWCNTs/EMMS/CPE displayed a long time stability (about 60 days) for monitoring of atropine. The ability of NiO@Pt/SWCNTs/EMMS/CPE as an electroanalytical tool for monitoring of atropine was investigated, and the recovery range was detected as to be 97.6%-104.25% for this goal.

Properties and Recent Advantages of N,N’-dialkylimidazolium-ion Liquids Application in Electrochemistry

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N,Nʹ-dialkylimidazolium-ion liquids is one of the important ionic liquids with a wide range of application as conductive electrolyte and in electrochemistry. The modified electrodes create a new view in fabrication of electroanalytical sensors. Many modifiers have beeen suggested for modification of electroanalytical sensor since many years ago. Over these years, ionic liquids and especially room temperature ionic liquids have attracted more attention due to their wide range of electrochemical windows and high electrical conductivity. N,Nʹ-dialkylimidazolium-ion liquids are one of the main important ionic liquids suggested for modification of bare electrodes and especially carbon paste electrodes. Although many review articles have reported onthe use of ionic liquids in electrochemical sensors, no review article has been specifically introduced so far on the review of the advantages of N,Nʹ-dialkylimidazolium ionic liquid. Therefore, in this review paper we focused on the introduction of recent advantages of N,Nʹ-dialkyl imidazolium ionic liquid in electrochemistry.

Development of Nanosensors Based Intelligent Packaging Systems: Food Quality and Medicine

The issue of medication noncompliance has resulted in major risks to public safety and financial loss. The new omnipresent medicine enabled by the Internet of things offers fascinating new possibilities. Additionally, an in-home healthcare station (IHHS), it is necessary to meet the rapidly increasing need for routine nursing and on-site diagnosis and prognosis. This article proposes a universal and preventive strategy to drug management based on intelligent and interactive packaging (I2Pack) and IMedBox. The controlled delamination material (CDM) seals and regulates wireless technologies in novel medicine packaging. As such, wearable biomedical sensors may capture a variety of crucial parameters via wireless communication. On-site treatment and prediction of these critical factors are made possible by high-performance architecture. The user interface is also highlighted to make surgery easier for the elderly, disabled, and patients. Land testing incorporates and validates an approach for prototyping I2Pack and iMedBox. Additionally, sustainability, increased product safety, and quality standards are crucial throughout the life sciences. To achieve these standards, intelligent packaging is also used in the food and pharmaceutical industries. These technologies will continuously monitor the quality of a product and communicate with the user. Data carriers, indications, and sensors are the three most important groups. They are not widely used at the moment, although their potential is well understood. Intelligent packaging should be used in these sectors and the functionality of the systems and the values presented in this analysis.

A new nickel-based co-crystal complex electrocatalyst amplified by NiO dope Pt nanostructure hybrid; a highly sensitive approach for determination of cysteamine in the presence of serotonin

A highly sensitive electrocatalytic sensor was designed and fabricated by the incorporation of NiO dope Pt nanostructure hybrid (NiO–Pt–H) as conductive mediator, bis (1,10 phenanthroline) (1,10-phenanthroline-5,6-dione) nickel(II) hexafluorophosphate (B,1,10,P,1,10, PDNiPF6), and electrocatalyst into carbon paste electrode (CPE) matrix for the determination of cysteamine. The NiO–Pt–H was synthesized by one-pot synthesis strategy and characterized by XRD, elemental mapping analysis (MAP), and FESEM methods. The characterization data, which confirmed good purity and spherical shape with a diameter of ⁓ 30.64 nm for the synthesized NiO–Pt–H. NiO–Pt–H/B,1,10, P,1,10, PDNiPF6/CPE, showed an excellent catalytic activity and was used as a powerful tool for the determination of cysteamine in the presence of serotonin. The NiO–Pt–H/B,1,10, P,1,10, PDNiPF6/CPE was able to solve the overlap problem of the two drug signals and was used for the determination of cysteamine and serotonin in concentration ranges of 0.003–200 µM and 0.5–260 µM with detection limits of 0.5 nM and 0.1 µM, using square wave voltammetric method, respectively. The NiO–Pt–H/B,1,10,P,1,10,PDNiPF6/CPE showed a high-performance ability for the determination of cysteamine and serotonin in the drug and pharmaceutical serum samples with the recovery data of 98.1–103.06%.

An Overview of the Applications of Nanomaterials and Nanodevices in the Food Industry

The efficient progress in nanotechnology has transformed many aspects of food science and the food industry with enhanced investment and market share. Recent advances in nanomaterials and nanodevices such as nanosensors, nano-emulsions, nanopesticides or nanocapsules are intended to bring about innovative applications in the food industry. In this review, the current applications of nanotechnology for packaging, processing, and the enhancement of the nutritional value and shelf life of foods are targeted. In addition, the functionality and applicability of food-related nanotechnologies are also highlighted and critically discussed in order to provide an insight into the development and evaluation of the safety of nanotechnology in the food industry.

Carbon Paste Modified Electrode as Powerful Sensor Approach Determination of Food Contaminants, Drug Ingredients, and Environmental Pollutants: A Review

Background:

Application of electrochemical sensors for analysis of food, biological and water polluting compounds helps to speed up their analysis in the real samples. Electrochemical sensors with low cost, fast response and portable ability are a better choice compared to traditional methods for analysis of electro-active compounds such as HPLC. Therefore, in recent years, many analytical scientists have suggested this type of analytical method for analysis of food, biological compounds and water pollutants.

Objective:

Due to low cost, easy modification and low non-faradic current, the carbon paste electrode is a suitable choice as a working electrode in the electrochemical and especially voltammetric analysis. On the other hand, modification of carbon paste electrode can improve the quality of the sensor for the analysis of electroactive compounds at nanomolar level.

A new analytical device incorporating a nitrogen doped lanthanum metal oxide with reduced graphene oxide sheets for paracetamol sensing

The novel N-CeO₂ nanoparticles decorated on reduced graphene oxide (N-CeO₂@rGO) composite has been synthesized by sonochemical method. The characterization of as prepared nanocomposite was intensely performed by UV-Vis, FT-IR, EDX, FE-SEM, HR-TEM, XRD, and TGA analysis. The synthesized nanomaterial was further investigated for its selective and sensitive sensing of paracetamol (PM) based on a N-CeO₂@rGO modified glassy carbon electrode. A distinct and improved reversible redox peak of PM is obtained at N-CeO₂@rGO nanocomposite compared to the electrodes modified with N-CeO₂ and rGO. It displays a very good performance with a wide linear range of 0.05-0.600 μM, a very low detection limit of 0.0098 μM (S/N = 3), a high sensitivity of 268 μA µM^-1 cm^-2 and short response time (<3 s). Also, the fabricated sensor shows a good sensibleness for the detection of PM in various tablet samples.

An electrochemical sensor for determination of tryptophan in the presence of DA based on poly(l-methionine)/graphene modified electrode

Electrocatalytic oxidation of l-Trp at poly(l-methionine)/graphene composite film modified glassy carbon electrode (PLME/GR/GCE) were investigated by differential pulse voltammetry.

Simultaneous electrochemical determination of acetaminophen, caffeine and ascorbic acid using a new electrochemical sensor based on CuO–graphene nanocomposite

A sensor using CuO nanoparticles and graphene was constructed. It is a useful tool for determining of acetaminophen, caffeine and ascorbic acid.