Electrochemical Sensor Research Articles

Bimetallic–organic MIL-125 frameworks for uric acid detection

The detection of uric acid (UA) is important not only in biomedicine and neurochemistry but also in disease diagnosis and pathology research. Herein, a family of bimetallic-organic frameworks, MIL-125(Ti–Cr)-xNH2 (x = 0 %, 25 %, 50 %, 75 %, and 100 %), was successfully prepared. MIL-125(Ti–Cr)-xNH2 series were used as electrochemical sensors for the detection of UA, and MIL-125(Ti–Cr)–0%NH2 exhibited the most promising behavior with 70 % carbon black doping in 0.1 M PBS (pH = 6.0). In addition, the as-prepared MIL-125(Ti–Cr)–0%NH2/GCE exhibited good stability and anti-interference behavior, which offered a promising platform for future utilization in real sample analysis.

Simple and sensitive electrochemical sensing of amethopterin by using carbon nanobowl/cyclodextrin electrode

Resulted from the severe side effects, the development of inexpensive, simple and sensitive method for amethopterin (ATP, an antineoplastic drug) is very important but it still remains a challenge. In this work, low cost nanohybrid composed of carbon nanobowl (CNB) and β-cyclodextrins (β-CD) (CNB-CD) was prepared with a simple autopolymerization way and applied as electrode material to develop a novel electrochemical sensor of ATP. Scanning-/transmission- electron microscopy, Fourier transform infrared spectrum, photographic image and electrochemical technologies were utilized to characterize morphologies and structure of the as-prepared CNB and CNB-CD materials. On the basic of the coordination advantages from CNB (prominent electrical property and surface area) and β-CD (superior molecule-recognition and solubility capabilities), the CNB-CD nanohybrid modified electrode exhibits superior sensing performances toward ATP, and a low detection limit of 0.002 μM coupled with larger linearity of 0.005-12.0 μM are obtained. In addition, the as-prepared sensor offers desirable repeatability, stability, selectivity and practical application property, confirming that this proposal may have important applications in the determination of ATP.

Facilely prepared Co-based MOF functionalized N, S-doped reduced graphene oxide for electrochemical non-enzymatic glucose sensing

Rational design of modified electrode materials is critical for electrochemical sensors. Metal-organic frameworks (MOFs), a novel sort of substance with porosity, has received widespread attention owing to various superior characteristics such as adjustable pore sizes, great surface area and controllable structures. Nevertheless, the poor charge transfer capability of MOFs leads to a general suppression of their electrochemical sensing performance. To solve this issue, compositing conductive substance with MOFs have been demonstrated to be an effective strategy. Herein, Co-based MOF (ZIF-67) functionalized N, S-doped reduced graphene oxide (N, S-RGO) heterostructure (ZIF-67/N, S-RGO) was fabricated through an in-situ synthesis method. The composite material was used in the modification of an electrode to construct a sensing platform for non-enzymatic glucose testing. The synergistic interaction of ZIF-67 and N, S-RGO not only provided more efficient active sites and larger surface areas, but also improved the electron transport efficiency and electrocatalytic performance. Under optimized conditions, the ZIF-67/N, S-RGO/GCE had a dynamic linear range of 1–3200 μM, with a detection limit of 0.33 μM (S/N = 3) for glucose detection. The sensing platform also provided excellent reproducibility, selectivity, and stability (70 % activity retained after 12 days). Furthermore, the sensor had the potential to apply for glucose determination in human serum. This work presented a novel strategy to the field of non-enzymatic glucose sensing and may provide effective coaching for optimizing the electrochemical sensing performance of other series of MOFs.

Towards sustainable and humane dairy farming: A low-cost electrochemical sensor for on-site diagnosis of milk fever

Milk fever is a metabolic disorder that predominantly affects dairy animals during the periparturient period and within four weeks of calving. Milk fever is primarily attributed to a decrease in the animal's serum Ca2+ levels. Clinical milk fever occurs when Ca2+ concentration drops below 1.5 mM (6 mg/dL). Without prompt intervention, clinical milk fever leads to noticeable physical symptoms and health complications including coma and fatality. Subclinical milk fever is characterized by Ca2+ levels between 1.5 and 2.12 mM (6–8.48 mg/dL). Approximately 50% of multiparous dairy cows suffer from subclinical milk fever during the transition to lactation. The economic impact of milk fever, both direct and indirect, is substantial, posing challenges for farmers. To address this issue, we developed a low-cost electrochemical sensor that can measure bovine serum calcium levels on-site, providing an opportunity for early detection of subclinical and clinical milk fever and early intervention. This calcium sensor is a scalable solid contact ion sensing platform that incorporates a polymeric calcium-selective membrane and ionic liquid-based reference membrane into laser-induced graphene (LIG) electrodes. Our sensing platform demonstrates a sensitivity close to the theoretical Nernstian value (29.6 mV/dec) with a limit of detection of 15.6 μM and selectivity against the species in bovine serum. Moreover, our sensor can detect Ca2+ in bovine serum with 91% recovery.

Detection of acetaminophen and P-aminophenol simultaneously by an electrochemical sensor based on Fe-NC derivatives attached with Ti3C2 QDs

In this paper, Ti3C2 QDs and Fe-ZIF-8 were synthesized by a straightforward hydrothermal method. Fe-ZIF-8 was pyrolyzed at high temperatures to obtain Fe-nanoclusters (Fe-NC). Then Fe-NC is mixed with Ti3C2 QDs to form a new composite material (Ti3C2 QDs/Fe-NC), and its microstructure and composition were analyzed by technology. The proposed material can detect acetaminophen (PA) and P-aminophenol (4-AP) simultaneously with excellent detection performance. With the best conditions, the linear ranges and detection limits were 0.50–210.00 μM, 0.03 μM (S/N = 3) and 0.50–150.00 μM, 0.06 μM (S/N = 3) for PA and 4-AP, respectively. The sensor has lower detection limits and wider linear ranges, and can successfully detect 4-AP and PA in river water and acetaminophen tablets at the same time, showing potential practical application prospects. Especially, this study reports the modification of MOF derivatives with Ti3C2 QDs for the first time, which expands the application scope of Quantum Dots and MOF derivatives.

Electrochemical sensing of Pb2+, Cu2+, and Hg2+ by an aminoclay-based porous covalent organic polymer/ multi-walled carbon nanotubes modified glassy carbon electrode

We present a novel electrochemical sensor for the simultaneous detection of Lead (Pb2+), Copper (Cu2+), and Mercury (Hg2+) ions in seafood samples using differential pulse anodic stripping voltammetry (DPASV) technique. The sensor incorporates an aminoclay-based porous covalent organic polymer (AC-PCOP) derived from the polymerization of aminoclay and 1,3,5-benzenetricarboxylic acid (trimesic acid). To enhance conductivity, the AC-PCOP is combined with multi-walled carbon nanotubes (MWCNTs) and utilized for modifying the surface of the glassy carbon electrode (GCE). The AC-PCOP was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, and infrared spectroscopy (IR). These analyses confirmed the presence of a hierarchical architecture in the AC-PCOP, which exhibited a spherical shape. The proposed modifier facilitates the deposition-stripping process and electron diffusion between electrolyte and heavy metal ions. Optimized conditions yielded limit of detections (LODs) of 0.0006, 0.0016, and 0.0003 nM, with linear ranges from 0.002 to 1000 nM, 0.005 to 1000 nM, and 0.001 to 1000 nM for Pb2+, Cu2+, and Hg2+, respectively. The sensor successfully measured these ions in seafood samples. Control experiments and validation were performed using cold vapor atomic absorption spectrometry (CVAAS) to determine the ions in the chosen food samples.

One-pot synthesis and hydrogen peroxide electrochemical sensing of 3D TiO2/MnO2 nanorods assembled microspheres.

Nanorods assembled 3D microspheres of TiO2/MnO2 were prepared via a simple one-pot hydrothermal approach. The resultant composite material exhibited remarkable electrocatalytic activity for hydrogen peroxide (H2O2) in comparison to each single component. The electrochemical sensor constructed with TiO2/MnO2 exhibited a linear relationship within the range 0.0001-5.6 mmol·L-1 for H2O2. The limit of detection (LOD) and sensitivity for H2O2 were 0.03 µmol·L-1 (S/N = 3) and 316.6 µA (mmol·L-1)-1cm-2. Moreover, this sensor can be employed to detect trace amount of H2O2 in serum and urine samples successfully, supporting an insight and strategy for a more sensitive electrochemical sensor.

Sulfur-functionalized graphene obtained by a non-thermal plasma process for simultaneous electrochemical determination of tert-butylhydroquinone and bisphenol A

Electrochemical sensors based on graphene have proven to be powerful tools for detecting bisphenol A (BPA) and tert-butylhydroquinone (TBHQ) individually. There are currently no reports of these analytes being detected simultaneously. By assembling graphene-based materials on gold surfaces, it is possible to improve the charge transfer of both analytes. This study utilized non-thermal plasma-assisted synthesis with a sulfur-containing precursor to functionalize graphene (S-Graph), resulting in the fabrication of an ultrasensitive electrochemical sensor that can detect both BPA and TBHQ, simultaneously. Compared with native graphene or a traditional surface of gold electrode, S-Graph/Au retained superior electrochemical activity for both analytes that showed significantly enhanced sensing performance, including a wide linear range, with a detection limit of 13 and 54 nmol L−1 for TBHQ and BPA, respectively. The enhanced long-term storage stability, as well as reproducibility showed that S-Graph is a promising strategy for promoting the application of novel graphene-based materials.

Sustainable synthesis of praseodymium tungstate: An electrochemical probe for detection of Ronidazole

Profligate consumption of antibiotics in animal and livestock husbandry indulged in antibiotic pollution. This collapses the natural balance of the ecosystem and results in various environmental health crises. Herein, we have developed an ultra-sensitive praseodymium tungstate (PWO) based electrochemical sensor to detect one such serious antibiotic, Ronidazole (RD). A facile synthesis strategy was applied to prepare PWO nanomaterial and their structural, functional, and elemental details were thoroughly examined with a wide range of spectroscopic measurements. The electrochemical properties were determined by performing impedance and voltammetry experiments. The high catalytic efficiency of the designed sensor was achieved by optimizing its performance under different parameters. Based on the outcomes, the designed PWO-based sensor offered an extremely low level of detection (0.3 nM) and exhibited a wide range of linearity (0.001 µM to 20.4 µM), high sensitivity (7.72 µA µM−1 cm−2), and good selectivity. Further, the performance of the electrochemical sensor was validated with good repeatability, reproducibility, and stability results. The practical applicability of the sensor was investigated by monitoring the RD in aquatic, biological, and pharmaceutical samples. The obtained results affirmed that the PWO sensor is an efficient platform for the real-time monitoring of RD.

Multi‐Parametric Decision System for Analytical Performance Assessment of Electrochemical (Bio)Sensors

AbstractMiniaturized three‐electrode electrochemical sensors (MES) are widely used in the advancement of innovative technologies for remote sensing applications. MESs consist of conductive electrodes that are applied onto an inert solid substrate using various techniques, such as photolithography, electroplating, and screen printing. Typical MES systems comprise working (WE) and counter (CE) electrodes based on gold (Au), paired with a reference electrode (RE) based on silver (Ag). This configuration is commonly selected due to Au's high conductivity, low resistance, and compatibility with robust organothiol chemistries, especially for the WE. Moreover, Ag is often preferred for REs owing to its low toxicity, stability, and high conductivity. Nevertheless, in uncontrolled environments outside of cleanrooms, both Au and Ag surfaces are prone to atmospheric contamination, resulting in significant sensor variability and compromised analytical performance. Therefore, it is crucial to integrate a pre‐processing stage into the sensor manufacturing process to guarantee the quality and cleanliness of MES electrode surfaces for sensor functionalization and precise electrochemical measurements. Considering the potential negative effects of methods tailored for a specific electrode material on another material, this study extensively investigates 18 different treatment methods for MESs incorporating Au CEs and WEs, along with Ag REs. Employing a multi‐parametric analysis, this study aims to identify the most effective treatment for a variety of electrode materials, thereby improving analytical accuracy and reproducibility for subsequent MES (bio)sensor applications.

Pore-Forming Toxin-Driven Recovery of Peroxidase-Mimicking Activity in Biomass Channels for Label-Free Electrochemical Bacteria Sensing.

The development of sensitive, selective, and rapid methods to detect bacteria in complex media is essential to ensuring human health. Virulence factors, particularly pore-forming toxins (PFTs) secreted by pathogenic bacteria, play a crucial role in bacterial diseases and serve as indicators of disease severity. In this study, a nanochannel-based label-free electrochemical sensing platform was developed for the detection of specific pathogenic bacteria based on their secreted PFTs. In this design, wood substrate channels were functionalized with a Fe-based metal-organic framework (FeMOF) and then protected with a layer of phosphatidylcholine (PC)-based phospholipid membrane (PM) that serves as a peroxidase mimetic and a channel gatekeeper, respectively. Using Staphylococcus aureus (S. aureus) as the model bacteria, the PC-specific PFTs secreted by S. aureus perforate the PM layer. Now exposed to the FeMOF, uncharged 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) molecules in the electrolyte undergo oxidation to cationic products (ABTS•+). The measured transmembrane ionic current indicates the presence of S. aureus and methicillin-resistant S. aureus (MRSA) with a low detection limit of 3 cfu mL-1. Besides excellent specificity, this sensing approach exhibits satisfactory performance for the detection of target bacteria in the complex media of food.

Intrinsically stretchable jellyfish-like gold nanowires film as multifunctional wearable chemical and physical sensors

We report on an intrinsically stretchable jellyfish-like gold nanowires film as a multifunctional wearable platform that can detect both chemical and physical biometrics. The film inherently exhibits multifunctionality, serving directly as an electrochemical electrode, strain sensor, temperature sensor, pressure sensor, and noncontact humidity sensor without the need of any additional materials. Our results highlight the excellent electrochemical properties, evidenced by a large electrochemical active surface area (EASA) of approximately 22.39 cm2 and the ability to withstand significant strain values up to 70 %. Leveraging these attributes, a stretchable electrochemical glucose biosensor was further designed with high sensitivity (45.40μA·mM−1·cm−2) and low limit of detection (10 μM). In addition, its sensing applications in strain, temperature, pressure and noncontact humidity were systematically explored. Impressively, the gold film is capable of monitoring multiple human motions and physiological signals, including joints bending, pulse motions, throat motions (e.g., drinking, speaking, swallowing and pronunciation recognition) and breathing. Furthermore, the film exhibited great versatility by integrating with 3D printing hydrogels, enabling customized patterning. The results demonstrate that our gold nanowires coating approach represent a new route to design multimodal soft wearable platforms for applications in personalized medicine and next-generation healthcare systems.

Ion gradient induced self-powered flexible strain sensor

To cope with energy hazards and reduce frequent battery replacement of strain sensors, various self-powered flexible strain sensors (including piezoelectric, triboelectric and electrochemical types) have developed recent years. However, the piezoelectric and triboelectric strain sensors cannot monitor static strain, and electrochemical strain sensors face the problem of performance degradation. Herein, inspired by ion gradient generators, a self-powered flexible strain sensor based on strain regulated ion gradient strategy is constructed. The sensor consists of elastic yarn coated with carbon nanotubes (CNTs), LiCl-filter paper (FP) and latex tube encapsulation. LiCl-FP with excellent water molecules absorption performance is wrapped on one side of the elastic yarn, forming a high humidity region in the sensor. The part of the elastic yarn that is not covered by LiCl-FP has weak water molecules absorption performance, forming a low humidity region in the sensor. The ions in the sensor move directionally from the high humidity region to the low humidity region, forming an ion gradient and generating voltage/current. The test results indicate that the sensor exhibits a wide strain detection range (0.5%–100%) and good repeatability (1000 times). The strain sensing mechanism can be attributed to the strain regulated ion gradient and the resistance strain effect. In addition, the strain sensing function of the sensor is verified by monitoring respiration. This work opens a new avenue for development of self-powered strain sensor using strain regulated ion gradient.

Bimetallic Fe/Co nanoalloy embedded in porous carbon as electrochemical sensor for acetaminophen detection

Ferro-alloys have been extensively studied in the field of electrochemical sensing due to their abundant earth reserves and excellent performances. In this work, serials of bimetallic Fe/Co nanoalloy@carbon composites (Fe/Co@C) were successfully prepared using Co-doped MIL-101(Fe) as templates and developed as excellent electrochemical sensors for acetaminophen (AP) detection. It was found that the atomic ratio of Fe/Co in the templates can significantly affect the electrochemical activity of the product. Among the prepared composites, Fe/Co@C-G2 (Fe/Co = 2:1) with high conductivity and large specific surface area presents the best electrochemical sensing performance. Under the optimal conditions, Fe/Co@C-G2 has a high sensitivity of 55.2 [Formula: see text]A [Formula: see text]M[Formula: see text] cm[Formula: see text], a wide linear range of 0.29-407.15 [Formula: see text]M, a low LOD of 0.09 [Formula: see text]M, good selectivity, excellent stability, and good repeatability. In addition, Fe/Co@C-G2 can also be used for real sample testing. This work expands the application of Fe/Co@C-based composites in electrochemical sensing.

Synthesis and Characterization of Palladium/Silver Modified Reduced Graphene Oxide–Nanocomposite Platform for Electrochemical Sensors

AbstractMetal nanoparticles incorporated into carbon nanostructures have tremendous applications in the field of nanosensors and other technologies. Herein, a nanohybrid of reduced graphene oxide modified with silver and/or palladium nanoparticles (Ag/Pd/rGO) was prepared by impregnation of Pd and Ag into the rGO platform and deposited on a glass carbon electrode. Palladium and silver nanoparticles improve the stability and durability of the sensor platform by preventing the agglomeration of graphene oxide sheets and providing chemical stability against environmental factors. This ensures long‐term reliability and repeatability of the sensor performance. The morphologies and microstructures of the as‐prepared nanohybrid were characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, UV–visible and infrared spectroscopy. The average crystallite size of PdAgNPs was found to be between 12 and 15 nm and demonstrated good dispersion across reduced graphene oxide sheets with high‐loading capacities. Thorough investigation of the electrochemical properties of the nanomaterial surfaces through cyclic voltammetry (CV) experiments, revealed distinct redox peaks for Ag+/Ag0 and Pd2+/Pd0 processes and demonstrated the excellent electrochemical properties of the prepared nanocomposites. The rGO‐PdAgNPs‐GCE had a diffusion coefficient value of 1.14×10−14 cm2 s−1 which is acceptable for electrochemical sensors as it is indicative of a fast response time and enhanced sensitivity to changes in gas concentration. The results obtained through thorough characterizations contributes to the novelty of the research by offering a deeper understanding of the material properties and the potential of the nanohybrid material for a broad application scope.

Electrochemical Detection of Melphalan in Biological Fluids Using a g-C3N4@ND-COOH@MoSe2 Modified Electrode Complemented by Molecular Docking Studies with Cellular Tumor Antigen P53.

Melphalan (Mel) is a potent alkylating agent utilized in chemotherapy treatments for a diverse range of malignancies. The need for its accurate and timely detection in pharmaceutical preparations and biological samples is paramount to ensure optimized therapeutic efficacy and to monitor treatment progression. To address this critical need, our study introduced a cutting-edge electrochemical sensor. This device boasts a uniquely modified electrode crafted from graphitic carbon nitride (g-C3N4), decorated with activated nanodiamonds (ND-COOH) and molybdenum diselenide (MoSe2), and specifically designed to detect Mel with unparalleled precision. Our rigorous testing employed advanced techniques such as cyclic voltammetry and differential pulse voltammetry. The outcomes were promising; the sensor consistently exhibited a linear response in the range of 0.5 to 12.5 μM. Even more impressively, the detection threshold was as low as 0.03 μM, highlighting its sensitivity. To further enhance our understanding of Mel's biological interactions, we turned to molecular docking studies. These studies primarily focused on Mel's interaction dynamics with the cellular tumor antigen P53, revealing a binding affinity of -5.0 kcal/mol. A fascinating observation was made when Mel was covalently conjugated with nanodiamond-COOH (ND-COOH). This conjugation resulted in a binding affinity that surged to -10.9 kcal/mol, clearly underscoring our sensor's superior detection capabilities. This observation also reinforced the wisdom behind incorporating ND-COOH in our electrode design. In conclusion, our sensor not only stands out in terms of sensitivity but also excels in selectivity and accuracy. By bridging electrochemical sensing with computational insights, our study illuminates Mel's intricate behavior, driving advancements in sensor technology and potentially revolutionizing cancer therapeutic strategies.

An Optimized MnO2-Ag Nanocomposite-Based Sensing Platform for Determination of 4-nitrophenol in Tomato Samples: Influences of Morphological Aspect of MnO2 Nanostructures and Synergic Effect on Electrochemical Kinetic Parameters and Analytical Performance

Abstract We have introduced potential modifiers synthesized from attached Ag nanoparticles (NPs) on MnO2 nanostructural surfaces, and fabricated an electrochemical sensor toward 4-nitrophenol (4-NP) detection. MnO2 with various morphologies (nanowires, nanorods, and nanosheets) has been prepared by hydrothermal and microwave-assisted hydrothermal methods, while AgNPs have been prepared by the simple electrochemical method. The structural characteristics and surface morphologies have been investigated via X-ray diffraction and scanning electron microscopy measurements. The effect of the change in morphology on the electrochemical behaviors and sensing performance has been investigated and discussed in detail. A parameter series involving the redox reaction of [Fe(CN)6]3-/4- and 4-NP reduction process has been calculated for each as-prepared modified electrode. Electrochemical results evidenced that benefiting from possessing outstanding electrochemical behaviors such as better conductivity, faster electron transfer ability, larger electroactive surface area, and higher charge transfer kinetics, MnO2 sheets-Ag/SPE has offered wider linear concentration range of 0.5-50 μM, LOD value as low as 0.073 µM, and high selectivity/repeatability. Furthermore, the optimization in the morphological aspect of MnO2 nanosheets and synergic effects arising from the effective combination with AgNPs make it become a model material for modifying electrode surfaces, indicating great potential for advanced electrochemical sensing applications.

Role of Silica, Carbon, and ZnO Nanomaterials in the Fabrication of Electrochemical Sensors for the Detection of Water Contaminants and Food Dye

AbstractSilica‐based nanomaterials have attracted huge attention for maximizing their safety and efficacy due to their nontoxicity, chemical and thermal stability, size tunability, and versatile functionality. Nanosilica with ZnO or carbon in a composite has excellent usage as an electrochemical sensor. Recent technological progression in nanotechnology and nanoscience has seen a number of applications of zinc oxide (ZnO) nanomaterials ranging from electronics, and sensing to environmental, and biomedical applications because of its various applications, multifunction, high specific surface area, stability, biocompatibility, nontoxicity, electrochemical activities, and so on. Carbon also has various advantageous properties like renewability, low ohmic resistance, and very stable response due to which carbon paste electrodes have attracted attention in the fabrication of electrochemical sensors. Electrochemical sensors are inexpensive, portable, and have excellent ability in detecting water contaminants, pesticides, disinfectants, pathogens, and different molecules. Artificial dyes are usually mixed with vegetable sauces, drinks, and other food items, which can cause cancer in human body. Voltametric methods with electrochemical sensors can be used to detect them in food samples. In this review, the present applications of ZnO and carbon nanomaterial‐based chemical sensors are meticulously studied to detect water contaminants and food dyes where nanosilica plays an important role as a sensor modifier.

A miniaturized additive-manufactured carbon black/PLA electrochemical sensor for pharmaceuticals detection

Additive manufacturing is a technique that allows the construction of prototypes and has evolved a lot in the last 20 years, innovating industrial fabrication processes in several areas. In chemistry, additive manufacturing has been used in several functionalities, such as microfluidic analytical devices, energy storage devices, and electrochemical sensors. Theophylline and paracetamol are important pharmaceutical drugs where overdosing can cause adverse effects, such as tachycardia, seizures, and even renal failure. Therefore, this paper aims at the development of miniaturized electrochemical sensors using 3D printing and polylactic acid-based conductive carbon black commercial filament for theophylline and paracetamol detection. Electrochemical characterizations of the proposed sensor were performed to prove the functionality of the device. Morphological characterizations were carried out, in which chemical treatment could change the surface structure, causing the improvement of the analytical signal. Thus, the detection of theophylline at a linear range of 5.00–150 μmol L−1 with a limit of detection of 1.2 μmol L−1 was attained, and the detection of paracetamol at a linear range of 1.00–200 μmol L−1 with a limit of detection of 0.370 μmol L−1 was obtained, demonstrating the proposed sensor effectively detected pharmaceutical drugs.

A sensitive enzyme-free electrochemical sensor based on ZnWO4/γ-Fe2O3 magnetic molecularly imprinted polymer for specific recognition and determination of Chloramphenicol

A chloramphenicol (CAP) electrochemical sensor based on zinc tungstate and magnetic hematite (ZnWO4/γ-Fe2O3) magnetic molecularly imprinted polymer (ZnWO4/γ-Fe2O3/MIP) is proposed. First, ZnWO4, γ-Fe2O3 nanomaterials were synthesized by one-step hydrothermal method, and then ZnWO4, magnetic nanoparticles were combined with molecularly imprinted polymers, that is, ZnWO4/γ-Fe2O3 was coated with a molecularly imprinted (MIP) shells by precipitation polymerization method to prepare magnetic molecularly imprinted nanomaterials, and then modified on glassy carbon electrodes to construct an electrochemical sensor for the determining of CAP. The results show that under the optimal conditions, the ZnWO4/γ-Fe2O3/MIP (MMIP) modified electrode has a stronger CAP detection reduction peak current than the one-component electrode, and exhibits better electrocatalytic activity, which is an excellent electrochemically modified electrode. Compared to magnetic non-molecular imprint sensors (MNIP), MMIP sensors have higher detection efficiency. The linear range of ZnWO4/γ-Fe2O3/MIP/GCE for the detection of CAP was 0.12 ∼ 1224 μM, and the detection limit was 0.034 μM, showing excellent stability and reproducibility, and good selectivity in the presence of different interferences. ZnWO4/γ-Fe2O3/MIP/GCE was applied to the detection of CAP in milk samples with satisfactory results.