A highly sensitive poly-arginine based MIP as an electrochemical sensor for selective detection of dimetridazole

Dual biomass-derived porous carbon heterogeneous functionalized mesoporous CuCo2O4 nanocomposite combined with molecularly imprinted polymers as an electrochemical sensing platform for hypersensitive and selective determination of dimetridazole contaminants

In this study, an original molecularly imprinted electrochemical sensor (MIECS) is prepared using layer-by-layer modification of sensitization nanomaterials (CuCo2O4/BPC-E) coupled with molecularly imprinted polymers (MIPs) for the ultrasensitive and rapid determination of dimetridazole (DMZ) contaminants. The biomass waste of eggshell (ES) powders subtly introduced in situ in the carbonization process of psyllium husk (PSH) substantially promotes the physicochemical properties of the resulting biomass-derived porous carbon (BPC-E). The large specific surface area and abundant pores provide a favourable surface for loading mesoporous CuCo2O4 with a spinel structure. The assembly of CuCo2O4/BPC-E on the gold electrode (GE) surface enhances the electrochemical sensing signal. The MIPs constructed using DMZ and o-phenylenediamine (oPD) as templates and functional monomers boost the targeted recognition performance of the analyte. The combined DMZ targets then undergo an electrochemical reduction reaction in situ with the transfer of four electrons and four protons. Under optimum conditions, the current response of differential pulse voltammetry (DPV) exhibits two linear ranges for DMZ detection, 0.01-10 μM and 10-200 μM. The limit of detection (LOD) is 1.8 nM (S/N = 3) with a sensitivity of 5.724 μA μM-1 cm-2. The obtained MIECS exhibits excellent selectivity, reproducibility, repeatability and stability. This electrochemical sensing system is applied to the detection of real samples (tap water, coarse fodder and swine urine), yielding satisfactory recoveries (90.6%-98.1 %), which are consistent with those obtained via HPLC. This finding verifies that the utility of MIECS for monitoring pharmaceutical and environmental contaminants and ensuring food safety.

Alternative method for rhamnolipids quantification using an electrochemical platform based on reduced graphene oxide, manganese nanoparticles and molecularly imprinted Poly(L-Ser)

Rhamnolipids (RHLs) are promising biosurfactants with important applications in several industrial segments. These compounds are produced through biotechnological processes using the bacteria Pseudomonas Aeruginosa. The main methods of analyzing this compound are based on chromatographic techniques. In this study, an electrochemical sensor based on a platform modified with reduced graphene oxide, manganese nanoparticles covered with a molecularly imprinted poly (L-Ser) film was used as an alternative method to quantify RHL through its hydrolysis product, acid 3-hydroxydecanoic acid (3-HDA). The proposed sensor was characterized microscopically, spectroscopically and electrochemically. Under optimized experimental conditions, an analytical curve was obtained in the linear concentration range from 2.0 × 10-12 mol L-1 to 1.0 × 10-10 mol L-1. The values estimated of LOD, LOQ and AS were 8.3 × 10-13 mol L-1, 2.7 × 10-12 mol L-1and 1.3 × 107 A L mol-1, respectively. GCE/rGO/MnNPs/L-Ser@MIP exhibits excellent selectivity, repeatability, and high stability for the detection of 3-HDA. Furthermore, the developed method was successfully applied to the recognition of the hydrolysis product (3-HDA) of RHLs obtained from guava agro-waste. Statistical comparison between GCE/rGO/MnNPs/L-Ser@MIP and HPLC method confirms the accuracy of the electrochemical sensor within a 95% confidence interval.

Molecularly Imprinted Heterostructure-Based Electrochemosensor for Ultratrace and Precise Detection of 2-Methylisoborneol in Water

Ultratrace 2-methylisoborneol (2-MIB, ∼ng/L) in source water is the main odorant in the algae-derived odor episodes, whose accurate on-site detection will have a promising application potential. Due to the chemical inertness of 2-MIB, sensitive and selective detection of 2-MIB remains much challenging. Herein, molecularly imprinted polymer cavities were polymerized on the heterostructure Ti3C2Tx@CuFc-metal-organic framework to selectively capture 2-MIB, where the heterostructure could catalyze the probe redox reaction of [Fe(CN)63-/4-] and amplify the corresponding current signals. The prepared electrochemical sensor showed higher sensitivity on 2-MIB detection than the reported ones. Excellent stability, reusability, and selectivity for 2-MIB detection were also verified. The linear range and limit of detection of our sensor for 2-MIB were optimized to 0.0001-100 μg/L and 30 pg/L, respectively, performing much better than the reported sensors. Comparable performance to gas chromatography-mass spectrometry was achieved when the sensor was applied to real water samples with or without 2-MIB standards. Overall, our research has made great progress in the application of an on-site sensor in 2-MIB detection and well advances the development of molecularly imprinted polymer-based electrochemical sensors.

Fergusonite-type rare earth niobates ANbO4 (A = Nd, Sm, and Eu) as electrode modifiers: deep insights into A site variations towards bifunctional electrochemical sensing applications

Lanthanide orthoniobates, LnNbO₄ (Ln = Nd, Sm, and Eu), are a domineering class of binary metal oxides with significant catalytic behavior and effective charge transfer ability, acting as eminent candidates to be explored as electrode materials. However, niobates have limitations to be used in sensing platforms due to the complicated synthetic procedures, which have been addressed in this study by proposing a facile hydrothermal tactic based on in situ homoleptic complex formation. All three niobates are isostructural with the monoclinic form of fergusonite structure, which was confirmed by XRD studies. The impact of the A site variation in the fergusonite crystal was verified by FTIR spectroscopy analysis, and the elemental composition was determined by XPS studies. FESEM with EDX spectroscopy obviously proved the morphological differences. Furthermore, a LnNbO₄-modified GCE was employed to detect pharmaceutical pollutants, namely, furazolidone (FZD) and dimetridazole (DMZ). Cyclic voltammetry studies were used to optimize the parameters of the sensing platform, and differential pulse voltammetry was performed to obtain the detection limits and linear range. SmNbO₄/GCE exhibited superior performance to other electrodes with a wide linear range of 0.01 μM to 264 μM and LOD values of 4 nM and 2 nM for FZD and DMZ, respectively. Finally, the feasibility of the proposed electrode in real-time analysis was studied by extending the voltammetry experiment to saliva and water samples.

Poly(3,4-ethylenedioxythiophene):Polystyrene Sulfonate-Modified Electrode for the Detection of Furosemide in Pharmaceutical Products

Furosemide (4-chloro-2-(furan-2-ylmethylamino)-5-sulfamoyl benzoic acid) is a widely used, FDA-approved drug prescribed for several symptoms associated with heart, kidney, liver failure, or chronic high blood pressure. In this work, a glassy carbon working electrode modified with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate is developed to detect furosemide (FURO) with high sensitivity and precise selectivity. The modified electrode was also characterized using field emission scanning electron microscopy, attenuated total reflectance-Fourier transform infrared, and cyclic voltammetry. Here, an efficient and cost- and time-efficient technique to study the furosemide mechanism of reaction in an acidic liquid medium is presented. An electrochemical oxidation of loop diuretic furosemide was investigated in a supporting electrolyte, 0.01 M of phosphate buffer (at a pH level of 4.0) at 25 ± 0.1 °C using a differential pulse voltammetric (DPV) technique. Under optimized parameters, the developed sensor displays a wide detection range of furosemide concentrations of 6.0 × 10^-6 to 1.0 × 10^-4 M with a detection limit of 2.0 × 10^-6 M using DPV. The presented sensor offers a robust and high-precision technique with an excellent reproducibility to detect furosemide in as a real sample such as urine and pharmaceutical products.

A Highly Selective Electrochemical Sensor Based on Molecularly Imprinted Copolymer Functionalized with Arginine for the Detection of Chloramphenicol in Honey

Developing an efficient method for chloramphenicol (CAP) detection is of great significance for food safety. Arginine (Arg) was selected as a functional monomer. Benefiting from its excellent electrochemical performance, which is different from traditional functional monomers, it can be combined with CAP to form a highly selective molecularly imprinted polymer (MIP) material. It overcomes the shortcoming of poor MIP sensitivity faced by traditional functional monomers, and achieves high sensitivity detection without compounding other nanomaterials, greatly reducing the preparation difficulty and cost investment of the sensor. The possible binding sites between CAP and Arg molecules were calculated by molecular electrostatic potential (MEP). A low-cost, non-modified MIP electrochemical sensor was developed for the high-performance detection of CAP. The prepared sensor has a wide linear range from 1 × 10^-12 mol L^-1 to 5 × 10^-4 mol L^-1, achieves a very low concentration CAP detection, and the detection limit is 1.36 × 10^-13 mol L^-1. It also exhibits excellent selectivity, anti-interference, repeatability, and reproducibility. The detection of CAP in actual honey samples was achieved, which has important practical value in food safety.

Advances in fabrication of molecularly imprinted electrochemical sensors for detection of contaminants and toxicants

Worldwide growing concerns about water contamination and pollution have increased significant interest in trace level sensing of variety of contaminants. Thus, there is demand for fabrication of low cost, miniaturized sensing device for in-situ detection of contaminants from the complex environmental matrices capable of providing selective and sensitive detection. Molecularly imprinted polymers (MIPs) has portrayed a substantial potential for selective recognition of various toxicants from a variety of environmental matrices, thus widely used as artificial recognition element in the electrochemical sensors (ECS) owing to their chemical stability, easy and low cost synthesis. The combination of nanomaterials modifiers with MIPs has endowed MIP-ECS with significantly improved sensing performance in the recent years, as the nanomaterial provide properties such as increased surface area, increased conductivity and electrocatalytic activity with enhanced electron transport phenomena, whereas MIPs provide selective recognition effect. In the present review, we have summarized the advances of MIP-ECS electrochemical sensors reported in last six years (2017-2022) for sensing of variety of contaminates including drugs, metal ions, hormones and emerging contaminates. Scope of computational modelling in design of sensitive and selective MIP-ECS is reviewed. We have focused particularly on the synthetic protocols for MIPs preparation including bulk, precipitation, electropolymerization, sol-gel and magnetic MIPs. Moreover, use of various nanomaterial as modifiers and sensitizers and their effects on the sensing performance of resulting MIP-ECS is described. Finally, the potential challenges and future prospects in the research area of MIP-ECS have been discussed.

Recent Trends in the Development of Carbon-Based Electrodes Modified with Molecularly Imprinted Polymers for Antibiotic Electroanalysis

Antibiotics are antibacterial agents applied in human and veterinary medicine. They are also employed to stimulate the growth of food-producing animals. Despite their benefits, the uncontrolled use of antibiotics results in serious problems, and therefore their concentration levels in different foods as well as in environmental samples were regulated. As a consequence, there is an increasing demand for the development of sensitive and selective analytical tools for antibiotic reliable and rapid detection. These requirements are accomplished by the combination of simple, cost-effective and affordable electroanalytical methods with molecularly imprinted polymers (MIPs) with high recognition specificity, based on their “lock and key” working principle, used to modify the electrode surface, which is the “heart” of any electrochemical device. This review presents a comprehensive overview of MIP-modified carbon-based electrodes developed in recent years for antibiotic detection. The MIP preparation and electrode modification procedures, along with the performance characteristics of sensors and analytical methods, as well as the applications for the antibiotics’ quantification from different matrices (pharmaceutical, biological, food and environmental samples), are discussed. The information provided by this review can inspire researchers to go deeper into the field of MIP-modified sensors and to develop efficient means for reliable antibiotic determination.

Modern and Dedicated Methods for Producing Molecularly Imprinted Polymer Layers in Sensing Applications

Molecular imprinting (MI) is the most available and known method to produce artificial recognition sites, similar to antibodies, inside or at the surface of a polymeric material. For this reason, scholars all over the world have found MI appealing, thus developing, in this past period, various types of molecularly imprinted polymers (MIPs) that can be applied to a wide range of applications, including catalysis, separation sciences and monitoring/diagnostic devices for chemicals, biochemicals and pharmaceuticals. For instance, the advantages brought by the use of MIPs in the sensing and analytics field refer to higher selectivity, sensitivity and low detection limits, but also to higher chemical and thermal stability as well as reusability. In light of recent literature findings, this review presents both modern and dedicated methods applied to produce MIP layers that can be integrated with existent detection systems. In this respect, the following MI methods to produce sensing layers are presented and discussed: surface polymerization, electropolymerization, sol–gel derived techniques, phase inversionand deposition of electroactive pastes/inks that include MIP particles.

Facile synthesis of neodymium stannate nanoparticles an effective electrocatalyst for the selective detection of dimetridazole in biological samples

In this work, pyrochlore neodymium stannate nanoparticles (Nd₂Sn₂O₇ NP) have been synthesized by a facile co-precipitation technique and employed as an electrode material on GCE for the determination of dimetridazole (DM) drug. The physical properties and texture of the Nd₂Sn₂O₇ NP were characterized by PXRD, Raman spectroscopy, FE-SEM, EDX mapping, XPS, and HR-TEM analytical studies. The electrocatalytic investigation of Nd₂Sn₂O₇ NP/GCE was carried out by CV, and DPV techniques. The fabricated Nd₂Sn₂O₇ NP/GCE shows a lower LOD of 6 nm towards the determination of DM and the calculated sensitivity is 0.61 μA μM^-1 cm^-2. In addition to that, the constructed sensor delivers notable repeatability, reproducibility, and superior selectivity with the existence of metal ions, biological molecules, and nitro compounds, enabling the electrochemical detection of DM. Furthermore, Nd₂Sn₂O₇ NP/GCE sensor displays acceptable recovery results in the real sample analysis in biological fluids such as human blood serum and human urine.

In situ electrochemical synthesis of graphene-poly(arginine) composite for p-nitrophenol monitoring

Para-Nitrophenol (p-nitrophenol) is a common industrial pollutant occurring widely in water bodies, yet actual monitoring methods are limited. Herein we proposed a fully electrochemically in situ synthesized graphene-polyarginine composite functionalized screen printed electrode, as a novel p-nitrophenol sensing platform. The electrode was characterized by morphologic, spectrometric and electrochemical techniques. p-nitrophenol in both pure aqueous solution and real water samples was tested. Results show a detection limit as low as the nanomolar level, and display a linear response and high selectivity in the range of 0.5-1250 μM. Molecular simulation reveals a detailed synergy between graphene and poly-arginine. The preferable orientation of nitrophenol molecules on the graphene interface in the presence of poly-arginine induces H- and ionic binding. This sensor is an ideal prototype for p-nitrophenol quantification in real waters.

Graphitic carbon nitride and APTES modified advanced electrochemical biosensor for detection of 17β-estradiol in spiked food samples

This work demonstrates a simple and inexpensive electrochemical biosensing pathway for selective and sensitive recognition of 17β-estradiol (E2) in environmental and food samples. The biosensing system is based on graphitic carbon nitride (g-C₃N₄) and a conductive polymer 3-aminopropyltriethoxysilane (APTES). The proposed biosensor shows the ability to detect E2 in attomolar levels within a wide linear logarithm concentration range of 1 × 10⁻⁶ to 1 × 10⁻¹⁸ mol L⁻¹ with a limit of detection (LOD) of 9.9 × 10⁻¹⁹ mol L⁻¹. The selectivity of the developed biosensor was confirmed by conducting the DPV of similarly structured hormones and naturally occurring substances. The proposed biosensor is highly stable and applicable to detect E2 in the presence of spiked food and environmental samples with satisfactory recoveries ranging from 95.1 to 104.8%. So, the designed electrochemical biosensor might be an effective alternative tool for the detection of E2 and other endogenous substances to attain food safety.

This work demonstrates a simple and inexpensive electrochemical biosensing pathway for selective and sensitive recognition of 17β-estradiol (E2) in environmental and food samples.

Highly sensitive electrochemical determination of the SARS-COV-2 antigen based on a gold/graphene imprinted poly-arginine sensor

The global COVID-19 pandemic starting at 2020 induced by the severe acute respiratory syndrome coronavirus 2 virus (SARS-CoV-2) has revealed a very pressing need for rapid, affordable and effective diagnosis for epidemic management and control. Although several commercialized analytical methods (e.g., reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay) have been developed for detecting SARS-CoV-2, they are expensive and time-consuming. Most recently, low-cost molecularly imprinted polymer (MIP)-based sensors have received attention. In this study, by introducing gold/graphene (Au/Gr) nanohybrids to modify a screen-printed carbon electrode (SPCE) and using arginine as the functional monomer, a simple and highly sensitive MIP sensor was proposed to detect SARS-CoV-2 nucleocapsid protein (ncovNP). By optimizing various influencing factors, the proposed MIP sensor shows wide linear range and low detection limit for ncovNP owing to excellent electrical property and large surface of Au/Gr and specific recognition ability of MIP, revealing important potential application for the effective early diagnosis of COVID-19.

Electrochemical sensor based on MIP for highly sensitive detection of 5-hydroxyindole-3-acetic acid carcinoid cancer biomarker in human biological fluids

An electrochemically synthetized nano-sensor based on molecularly imprinted polypyrrole (MIPPy) was successfully developed for the detection of 5-hydroxyindole-3-acetic acid (5-HIAA) in human biological fluids namely serum, urine, and plasma. The imprinted glassy carbon electrode was prepared by electropolymerisation of pyrrole via cyclic voltammetry (C.V). After completely leaching the imprinted molecules from the polymeric network, complementary cavities are created. The developed MIPPy sensor, under optimized conditions, shows a high sensitivity towards the target molecule (LOQ = 5 × 10^-11 M). Moreover, it presents a wide linear response in the range of 5 × 10^-11 - 5 × 10^-5 M (R² > 0.999) with a detection limit of 15 × 10^-12 M. In order to evaluate the selectivity of the MIPPy film, several structural analogues and compounds forming the real matrices were tested. The obtained results show an excellent recovery rate (between 98.86 and 101.52%) proving the promising application of the proposed nano-sensor in the detection of 5-HIAA in human biological fluids without any significant interference recorded.

Well-Designed Construction of Yttrium Orthovanadate Confined on Graphitic Carbon Nitride Sheets: Electrochemical Investigation of Dimetridazole

Antibiotics are the most important drugs for people and animals to fight bacterial illnesses. Overuse of antibiotics has had unintended consequences, such as antibiotic resistance and ecosystem eradication owing to toxic chemical discharge, which have a negative influence on the biome. Herein, we report the synthesis of a hollow ellipsoid-shaped yttrium vanadate/graphitic carbon nitride (YVO₄@CN) nanocomposite by a hydrothermal approach followed by a sonochemical method for the effective detection of dimetridazole (DMZ). The synergic and coupling effect between both the phases offer non-linear cumulative ramifications which can positively enhance the individual properties of the materials under consideration. This positive hybrid effect increases the conductivity, shortens the ion-diffusion pathway, enhances the electron/ion transportation, and provides more active sites and electron-conducting channels. The accurate optimization of the experimental conditions proposes good electrocatalytic activity for the YVO₄@CN catalyst, exhibiting a good response toward DMZ detection. It reveals an extensive linear concentration range (0.001-153.3 and 176.64-351.6 μM), a low detection limit (0.8 nM), higher sensitivity (4.98 μA μM^-1 cm^-2), appreciable selectivity, increased operational stability (2200 s), and good cycle stability (60 cycles). The electrochemical performance of YVO₄@CN indicates its practical application in real-time sample analysis of several families of nitroimidazole drugs.

Electroanalytical Overview: Electrochemical Sensing Platforms for Food and Drink Safety

Robust, reliable, and affordable analytical techniques are essential for screening and monitoring food and water safety from contaminants, pathogens, and allergens that might be harmful upon consumption. Recent advances in decentralised, miniaturised, and rapid tests for health and environmental monitoring can provide an alternative solution to the classic laboratory-based analytical techniques currently utilised. Electrochemical biosensors offer a promising option as portable sensing platforms to expedite the transition from laboratory benchtop to on-site analysis. A plethora of electroanalytical sensor platforms have been produced for the detection of small molecules, proteins, and microorganisms vital to ensuring food and drink safety. These utilise various recognition systems, from direct electrochemical redox processes to biological recognition elements such as antibodies, enzymes, and aptamers; however, further exploration needs to be carried out, with many systems requiring validation against standard benchtop laboratory-based techniques to offer increased confidence in the sensing platforms. This short review demonstrates that electroanalytical biosensors already offer a sensitive, fast, and low-cost sensor platform for food and drink safety monitoring. With continued research into the development of these sensors, increased confidence in the safety of food and drink products for manufacturers, policy makers, and end users will result.

Biomimetic electrochemical sensors: New horizons and challenges in biosensing applications

The urge to meet the ever-growing needs of sensing technology has spurred research to look for new alternatives to traditional analytical methods. In this scenario, the glucometer is the flagship of commercial electrochemical sensing platforms, combining selectivity, reliability and portability. However, other types of enzyme-based biosensors seldom achieve the market, in spite of the large and increasing number of publications. The reasons behind their commercial limitations concern enzyme denaturation, and the high costs associated with procedures for their extraction and purification. In this sense, biomimetic materials that seek to imitate the desired properties of natural enzymes and biological systems have come out as an appealing path for robust and sensitive electrochemical biosensors. We herein portray the historical background of these biomimicking materials, covering from their beginnings until the most impactful applications in the field of electrochemical sensing platforms. Throughout the discussion, we present and critically appraise the major benefits and the most significant drawbacks offered by the bioinspired systems categorized as Nanozymes, Synzymes, Molecularly Imprinted Polymers (MIPs), Nanochannels, and Metal Complexes. Innovative strategies of fabrication and challenging applications are further reviewed and evaluated. In the end, we ponder over the prospects of this emerging field, assessing the most critical issues that shall be faced in the coming decade.

A simple platform for the electro-catalytic detection of the dimetridazole using an electrochemical sensor fabricated by electro-deposition of Ag on carbon graphite: application: orange juice, tomato juice and tap water

The objective of this paper is to evaluate and optimize the experimental parameters of the electro-deposition of silver atom nuclei on a graphite carbon paste to elaborate an electrochemical sensor. The electro-deposition process was performed using the cyclic voltammetry. The electrochemical studies show that the deposited silver micro-particle array offers an excellent electro-catalytic activity towards the NO₂ attractor group of the dimetridazole side chain. SEM morphological analysis of the silver deposits indicates the presence of a large number of Ag micro-particles on the graphite carbon with good nucleation. The size of the Ag micro-particles is of the order of 19,7621 μm and their distribution is normal over the entire range of the pulp. DRX analysis of the deposit also indicates that the microcrystalline structure of the silver microcrystals in the deposit is face-centered cubic. The electrochemical behavior of dimetridazole is totally irreversible, the transfer process is controlled by diffusion phenomena on the surface of the electrode covered by a silver deposit realized μAg@CPE. The analytical performance of the constructed electrode shows a good selectivity. Calibration curves for the detection of dimetridazole have been drawn in the concentration range of 3,5 × 10⁻⁴ mol/L to 10⁻⁶ mol/L using cyclic voltammetry method, with a detection and quantification limits of 6.565 × 10⁻⁷ mol/L and 2.216 × 10⁻⁶ mol/L respectively. The applicability of the constructed electrode has been tested in real samples including orange juice, tomato juice, tap water. The results obtained show a recovery rate above 94%, which is very satisfactory.

Molecularly Imprinted Polymer Based GCE for Ultra-sensitive Voltammetric and Potentiometric Bio Sensing of Topiramate

Topiramate (TOP) drug is classified as one of the most commonly used human drugs for anticonvulsants and antiepileptic, so its rapid detection and monitoring is of great importance. In this work, new potentiometric (MIP/PVC/GCE) and voltammetric (MIP/GO/GCE) sensors for the selective and sensitive determination of TOP were fabricated based on the molecularly imprinted polymer (MIP) approach. The MIP was synthesized by the polymerization of acrylamide and methacrylic acid as monomers, in the presence of TOP as a template and ethylene glycol dimethacrylate as a cross-linker. The obtained products were characterized by FT-IR, SEM, BET, and EDX. The MIP was embedded in a plasticized polyvinyl chloride membrane and used as a potentiometric sensor for sensing TOP. Alternatively, the synthesized MIP and graphene oxide (GO) were deposited layer-by-layer on the surface of GCE to construct a voltammetric sensor for studying the electrochemical behavior of the drug. Under optimized conditions, both electrochemical sensors showed excellent linear relationships between the concentration of TOP and the response signals of MIP/GO/GCE or MIP/PVC/GCE sensors in the 2.7 × 10^-10 to 4.9 × 10^-3 M and 1 × 10^-9 to 3.4 × 10^-3 M ranges, respectively. Also, both sensors have good reproducibility and high stability for up to 15 days for a voltammetric sensor and 28 days for a potentiometric sensor. The utility of these sensors was checked for TOP analysis in different real samples with good recovery (92.8 - 99%).

N-Hydroxysuccinimide crosslinked graphene oxide–gold nanoflower modified SPE electrode for sensitive detection of chloramphenicol antibiotic

Here we introduce a composite material that consists of graphene oxide (GO) sheets crosslinked with N-hydroxysuccinimide (NHS) and functionalized with gold nanoflowers (AuNFs). Furthermore, a screen printed electrode (SPE) modified with the introduced composite is electrochemically reduced to obtain an SPE/rGO–NHS–AuNFs electrode for sensitive and selective determination of chloramphenicol (CAP) antibiotic drug. The morphological structure of the as-prepared nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, cyclic voltammetry, Fourier-transform infrared spectroscopy and electrochemical impedance spectroscopy. The proposed sensor demonstrated excellent performance with a linear concentration range of 0.05 to 100 μM and a detection limit of 1 nM. The proposed electrode offers a high level of selectivity, stability, reproducibility and a satisfactory recovery rate for electrochemical detection of CAP in real samples such as blood serum, poultry feed, milk, eggs, honey and powdered milk samples. This further demonstrates the practical feasibility of the proposed sensor in food analysis.

Here we introduce a composite material that consists of graphene oxide (GO) sheets crosslinked with N-hydroxysuccinimide (NHS) and functionalized with gold nanoflowers (AuNFs).