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Nivalenol as a mycotoxin pesticide is toxic to humans and animals and causes major health problems including hemorrhage, anemia, and vomiting. Thus, the need for fast and reliable analytical systems in terms of the management of health risks resulting from nivalenol exposure has increased in recent years. The aim of this study involved a novel molecularly imprinted quartz crystal microbalance sensor preparation based on sulphur-incorporating cobalt ferrite for nivalenol detection in rice samples. For this aim, cobalt ferrite and sulfur incorporated cobalt ferrite were successfully synthesized by sol–gel and calcination methods, respectively. Then, nivalenol imprinted quartz crystal microbalance chips based on cobalt ferrite and sulfur incorporated cobalt ferrite were prepared by an ultraviolet polymerization technique including N,N′-azobisisobutyronitrile as the initiator, ethylene glycol dimethacrylate as the cross-linker, methacryloylamidoglutamic acid as the monomer, and nivalenol as the analyte. After some spectroscopic, electrochemical and microscopic characterization studies, the developed sensor was applied to rice grain samples for the determination of nivalenol. The linearity of the prepared sensor was observed to be 1.0–10.0 ng L−1and the limit of quantification and detection limit were found to be 1.0 and 0.33 ng L−1, respectively. Finally, the high selectivity, repeatability, and stability of the prepared sensor based on sulphur-incorporating cobalt ferrite and a molecularly imprinted polymer can ensure safe food consumption worldwide.

Phenylketonuria (PKU) is a critical disease in the disorder of amino acid metabolism, which mostly emerges in children. The most common method used in PKU treatment is the detection of l-phenylalanine (PHEA) as the biomarker of PKU. In the present work, a new molecularly imprinted electrochemical electrode based on WS2nanoflowers (NFs) on N,B-doped graphene (WS2NFs/N,B-GR) is presented for PHEA assay in milk samples. First of all, WS2NFs/N,B-GR was synthesized via a high-efficiency hydrothermal synthesis. Cyclic voltammetry was applied to the electrochemical cell, including PHEA as a template molecule and pyrrole as a monomer, to form PHEA-imprinted electrochemical electrodes. Then, the structural and morphological features of WS2NFs and WS2NFs/N,B-GR were investigated in detail by various analytical methods. The limit of quantification and limit of detection values were obtained as 1.0 × 10–11and 3.0 × 10–12M, respectively, by a PHEA-imprinted electrochemical electrode. Finally, a PHEA-imprinted electrochemical sensor having a high degree of selectivity, stability, and reusability is presented in the literature for early diagnosis of PKU.

5-Hydroxymethyl furfural (HMF) is an intermediate produced by dehydrating sugars, such as fructose, sucrose, and glucose, in an acidic medium or during the Maillard reaction. It also occurs due to the storage of sugary foods at inappropriate temperatures. In addition, HMF is seen as a quality criterion in products. In this study, a novel molecularly imprinted electrochemical sensor based on graphene quantum dots incorporated NiAl2O4(GQDs–NiAl2O4) nanocomposite was presented for the selective determination of HMF in coffee samples. Various microscopic, spectroscopic, and electrochemical methods were carried out for the structural characterizations of GQDs–NiAl2O4nanocomposite. The molecularly imprinted sensor was prepared by multi-scanning using cyclic voltammetry (CV) in the presence of 100.0 mM pyrrole monomer and 25.0 mM HMF. After method optimization, the sensor revealed linearity towards HMF in the range of 1.0–10.0 ng L−1with a detection limit (LOD) of 0.30 ng L−1. The developed MIP sensor's high repeatability, selectivity, stability, and fast response ability can provide reliable HMF detection in beverages, such as coffee, which is heavily consumed.

Background: Until now, several methods such as spectroscopic methods and chromatographic techniques have been developed for the determination of biomolecules, drug or heavy metals. Nevertheless, the crucial interference problems are present in these methods. Due to these reasons, more sensitive, favorable portability, low-cost, simple and selective sensors based on nanocomposites are needed in terms of health safety. In the development of electrochemical nanosensor, the nanomaterials such as graphene/graphene oxide, carbon and carbon nitride nanotubes are utilized to improve the sensitivity. Objective: The nanomaterials such as graphene/graphene oxide, carbon and carbon nitride nanotubes have important advantages such as high surface area, electrical conductivity, thermal and mechanical stability. Hence, we presented the highly selective methods for sensitive sensor applications by molecular imprinting technology in literature. This technology is a polymerization method around target molecule. This method provides the specific cavities to analyte molecule on the polymer surface. Hence, the selective sensor is easily created for biomedical and other applications. Novel electrochemical sensors based on nanocomposite whose surface is coated with Molecular Imprinting Polymer (MIP) are developed and then applied to the selective and sensitive detection in this study. Until now, we have presented several reports about nanocomposite based sensor with MIP.

We report the synthesis of Ru@Au nanoparticle involved l-cysteine functionalized reduced graphene oxide (rGO) composites (NSrGO/Ru@AuNPs). The nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The electrochemical determination of curcumin (CR) has been studied using square wave voltammetry (SWV) on a glassy carbon electrode (GCE) modified with NSrGO/Ru@AuNP composites (NSrGO/Ru@AuNPs/GCE). The effective surface areas (ESAs) of the rGO/GCE and NSrGO/Ru@AuNPs/GCE were calculated to be 347 cm2mg−1and 1289 cm2mg−1, respectively. These results show that the electrochemical surface area of the NSrGO/Ru@AuNPs/GCE is 3.71 times higher than that of the rGO/GCE. The developed method was also applied successfully for the determination of CR in plasma and the linearity range of CR was 0.001–0.1 nM with a detection limit of 2.0 × 10−13M.

The detection of acute myocardial infarction (AMI) directly depends on the concentration of the cardiac troponin I (CTnI) in human blood plasma. In this study, the sensitive, selective, and fast sandwich-type electrochemical CTnI immunosensor was developed by using nitrogen and boron dopped graphene quantum dots (N-B-GQDs) as electrode platform and two-dimensional (2D) Ce dopped SnO2/SnS2(Ce-SnO2/SnS2) as signal amplification. In preparation of electrochemical CTnI immunosensor, the coordinated covalent bond between capture antibody (anti-CTnI-Ab1) and N-B-GQDs as electrode platform led to immobilization of anti-CTnI-Ab1and the strong esterification between secondary antibody (anti-CTnI-Ab2) and thioglycolic acid modified Ce-SnO2/SnS2resulted in anti-CTnI-Ab2conjugation. Finally, the resultant electrochemical CTnI immunosensor was formed via antigen-antibody interaction. High resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), fouirer transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and raman spectroscopy as well as some electrochemical characterization techniques including cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the prepared immunosensor. The detection limit (LOD) of CTnI in plasma samples was calculated as 2.00 fg mL-1, making it an effective tool for acute myocardial infarction testing.

Methyl parathion (MP) is an organophosphate chemical agent. Due to low solubility and bioaccumulation, it results in serious health problems. Electrochemical recognition based on graphitic carbon nitride (CN) incorporated hexagonal boron nitride (HBN) nanosheets and molecularly imprinted polymer (MIP) was presented for methyl parathion (MP) detection. Scanning electron microscopy (SEM), X-ray diffraction (XRD) method, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized for characterizations. After that, MP imprinted voltammetric sensor on CN-HBN nanocomposite was carried out in the presence of 100.0 mM pyrrole containing 25.0 mM MP via CV. 1.0 × 10−12–2.0 × 10−9 M and 2.0 × 10−13 M were found as the linearity range and the detection limit (LOD). Finally, MP imprinted sensor was applied to orange juice samples for MP analysis.

Electrochemical recognition based on Au@nitrogen-doped carbon quantum dots@Ag core-shell (Au NPs@NCDS@Ag NPs) composite including molecular imprinted polymer (MIP) was presented for metobromuron (MBN) detection. Firstly, novel triple-layered core-shell structure including gold nanoparticles core, nitrogen-doped carbon quantum dots interlayer and silver nanoparticles outside shell was synthesized by the reduction of chloroauric acid (HAuCl4), silver nitrate (AgNO3) in the presence of NCDS. Secondly, MBN imprinted polymer on Au NPs@NCDS@Ag NPs composite was electrochemically performed in the presence of pyrrole and MBN via cyclic voltammetry (CV). Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), energy-dispersive x-ray (EDX) spectroscopy, x-ray diffraction (XRD) method and electroanalytical methods such as CV, chronoamperometry (CA), electrochemical impedance spectroscopy (EIS) were performed for characterizations of core-shell structure. MBN imprinted electrode showed high electrocatalytic performance and the linear range of 1.0 × 10−12–2.0 × 10−9M and detection limit (LOD) of 2.0 × 10−13M were obtained.

Phenylethanolamine A (PEA) is used illegally and deposited in animal tissues. Due to the reason, it causes acute poisoning and symptoms of muscular tremors, nervousness. In present article, Ru@Au core-shell nanoparticles (Ru@Au NPs) involved in carbon nitride nanotubes (C3N4NTs) functionalized graphene quantum dots (GQDs) nanocomposite based molecular imprinted polymer (MIP) was formed for PEA recognition. Firstly, C3N4NTs@GQDs nanocomposite was prepared by means of hydrothermal treatment. Secondly, this nanocomposite was functionalized with 2-aminoethanethiol (AET) via the affinity of gold-sulfur for binding Ru@Au NPs. After that, PEA imprinted voltammetric sensor was prepared in presence of 100.0 mM phenol as monomer containing 25.0 mM PEA by cyclic voltammetry (CV). All nanomaterials’ formation and properties were highlighted with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray analysis (EDX), raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). 1.0 × 10−12- 1.0 × 10−9M and 2.0 × 10−13M were founded as the linearity range and the detection limit (LOD). Finally, PEA imprinted glassy carbon electrode (GCE) was used for urine sample analysis in presence of the other competitor agents such as clenbuterol (CLE), ractopamine (RAC) and salbutamol (SAL). In addition, the stability and repeatability of prepared sensor was investigated.

A new diethylstilbestrol (DES) imprinted sensor approach based on gold nanoparticles (AuNPs) incorporated two-dimensional (2D) hexagonal boron nitride (2D-hBN) nanosheets was presented for DES detection. The methods such as scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) method, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for all nanomaterials’ characterizations. DES imprinted sensor was prepared in presence of 100.0 mM pyrrole containing 25.0 mM DES by CV. The developed method was validated and 5.0 × 10−12−1.0 × 10−8 M and 1.0 × 10−13 M were founded as the linearity range and the detection limit (LOD). DES imprinted glassy carbon electrode (GCE) was applied in presence of the natural estrogens such as estrone (E1), estradiol (E2) and estriol (E3) and the other agents such as hydroquinone (HYD) and catechol (CAT).

Cypermethrin ([RS]-alpha-cyano-3-phenoxybenzyl [1RS, 3RS; 1RS, 3SR]-3-[2,2-dichlorovinyl]-2,2-dimethylcyclopropanecarboxylate) is a crucial pyrethroid and it is generally used as poison against crop pests, domestic insects and ectoparasites in farmed fish. A new molecular imprinted sensor approach based on core-shell type nanoparticles (Fe@AuNPs) incorporated two-dimensional (2D) hexagonal boron nitride (2D-hBN) nanosheets was presented for cypermethrin (CYP) detection in wastewater samples. All nanomaterials’ formation and properties were highlighted with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) method, energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CYP imprinted voltammetric sensor was improved in presence of 80.0 mM phenol containing 20.0 mM CYP by CV. 1.0 × 10−13- 1.0 × 10−8 M and 3.0 × 10−14 M were founded as the linearity range and the detection limit (LOD). Finally, CYP imprinted glassy carbon electrode (GCE) was used for wastewater sample analysis in presence of the other competitor agents such as deltamethrin (DEL), tetrametrin (TET) and permethrin (PER). In addition, the prepared sensor was investigated in terms of stability and repeatability.

Fuel cells have important applications in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. Pt/Pd nanoparticles/polyoxometalate/ionic liquid (ILs) nanohybrid synthesized for the first time and characterized by transmission electron microscope, scanning electron microscope, X-ray photo electron spectroscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction method. A cost-effective catalyst has been developed on Pt/Pd nanoparticles/polyoxometalate/ionic liquid nanohybrid. The developed catalyst based on bimetallic nanoparticle demonstrates effective methanol oxidation in comparison with catalysts on monometallic nanoparticle and polyoxometalate/ionic liquid nanohybrid.

Chlorpyrifos (CHL) is organophosphate insecticide and has low water solubility (1.39 mg/L). CHL is known to produce toxic effects by inhibiting the acetylcholinesterase enzyme activity. Because of this, the important health problems occur worldwide. Hence, it is important to detect the concentration of CHL at the sensitive levels in environmental waters. In this study, a novel molecular imprinted voltammetric sensor based on carbon nitride nanotubes (C3N4NTs) decorated with graphene quantum dots (GQDs) modified glassy carbon electrode (GCE) was developed for determination of CHL. The unique C3N4NTs@GQDs nanohybrid was synthesized by hydrothermal treatment. CHL imprinted GCE based on C3N4NTs@GQDs nanohybrid was prepared via electropolymerization process of 100 mM pyrrole as monomer in the presence of phosphate buffer solution (PBS) (pH 7.0) containing 25 mM CHL. The prepared nanomaterials were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The linearity range and the detection limit of the method were calculated as 1.0 × 10−11–1.0 × 10−9M and 2.0 × 10−12M, respectively. The sensor was applied to wastewater samples with good selectivity and recovery. The stability and selectivity of the voltammetric sensor were also reported.

In this study, polymeric membrane was modified with reduced graphene oxide and used for the effective determination of tobramycin from real samples using prepared molecular imprinted electrochemical sensor. The use of graphene oxide in the membrane filtration process as an additive material presents great opportunities and possibilities for membrane technology. The purpose of this study was to improve the structural and mechanical features of polymeric membrane by adding reduced graphene oxide, which already possesses high mechanical and chemical properties for the separation process, as well as developing a selective and sensitive electrochemical sensor. For this purpose, transport of tobramycin was provided from the milk sample through the modified rGO/PIM. Tobramycin was transported by 80.08% RF from donor to acceptor phase at the end of 10 days. The prepared sensor offers sensitivity and selectivity of determining tobramycin and is utilized many facilities.

Melamine (MEL) has high nitrogen rich content. Because of this situation, it has been illegally added to dairy products by producers to obtain a higher readout of apparent protein content. This has been a cause of serious diseases and many infants have been intoxicated because the addition of MEL into food products can cause death. In this report, a novel molecular imprinted voltammetric sensor based on carbon nitride nanotubes (C3N4NTs) modified glassy carbon electrode (GCE) was presented for determination of MEL. The developed surfaces were characterized using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). MEL imprinted GCE was prepared via electropolymerization process of 100 mM phenol as monomer in the presence of phosphate buffer solution (PBS) (pH 7.0) containing 25 nM MEL. The linearity range and the detection limit of the method were calculated as 1.0 × 10−10– 5.0 × 10−9M and 1.0 × 10−11M, respectively. The voltammetric sensor was applied to milk samples with good selectivity and recovery. The stability and reproducibility of the voltammetric sensor were also reported.

A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughout world. A facile and cost-effective catalysts have been developed on polyoxometalate (NaPWO) functionalized graphene quantum dots (GQDs) with several mono-metallic and bi-metallic nanoparticles such as platinum nanoparticles (PtNPs), palladium nanoparticles (PdNPs) and platinum-palladium nanoparticles (Pt-PdNPs). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) method. According to TEM images, the average particle sizes of PtNPs and PdNPs were found to be approximately 20–30 nm. The Pt-PdNPs/NaPWO/GQDs also exhibited a higher peak current for methanol oxidation than those of comparable PdNPs/NaPWO/GQDs and PtNPs/NaPWO/GQDs, thus providing evidence for its higher electro-catalytic activity.

The cost-effective technique has been performed on 2-aminoethanethiol (2-AET) functionalized GQDs with mono-metallic and bi-metallic nanoparticles such as rod gold nanoparticles (rAuNPs) and rod gold-platinum nanoparticles (rAu-PtNPs). In present study, the structures of nanomaterials were highligted by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and X-ray diffraction (XRD) method. In addition, glassy carbon electrode (GCE) modified with rAu-PtNPs/GQDs nanomaterial (rAu-PtNPs/GQDs/GCE) was utilized in milk sample analysis.