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The cytotoxic dosage of exposed drug waste is frequently discharging on aquatic surfaces via wastewater treatment plants and pharma industries. Early detection of these drug wastes with a reliable and accurate are in great need. In this report, a noble metal effectively doped on oxidized one-dimensional (1D) single-walled carbon nanotube and abundant oxygen functional groups presenting two-dimensional (2D) graphene oxide on its surface, and hydrophobic cavities are the promising selector towards electrochemical oxidation of Naproxen (NPZ). A hybrid nanocomposite Au@f-CNT/GO was engineered by the ultrasound-assist sonication method and employed for the ultra-quantification of the therapeutic drug NPZ. In addition, various physicochemical and analytical techniques were utilized to confirm the successful formation of composite and principal detection of NPZ. Au@f-CNT/GO fabricated glassy carbon electrode exhibits a low resistance and higher electrocatalytic activity toward NPZ sensing. In addition, under the optimized condition, the sensor demonstrates an acceptable linear range of 100 nM − 15.6 µM, a lower limit of detection of 14 nM (S/N = 3), and higher sensitivity of 1.7484 μA μM−1 cm2. Furthermore, the proposed sensor has high selectivity, stability, reproducibility, and repeatability. Moreover, real sample analysis shows appreciable recovery results of 96 to 99% which strongly suggests that the proposed sensor has potential applicability for the sensitive detection of NPZ in the various water and biological samples.

In this report, 3D flower-like cobalt phosphate (Co3(PO4)2, CPO) was prepared through a facile co-precipitation method towards voltammetric sensing of rutin (RU), quercetin (QCT) and also employed for supercapacitor application. The structural morphologies were analyzed by various analytical techniques. The Brunauer–Emmett–Teller analysis of CPO displays a specific surface area of 40.885 m2 g−1 and a mesopore volume of 0.0108 cm3 g−1, which provides more catalytic sites, and a good electron transfer pathway that leading to promote enhanced electrochemical performance for detection of RU, and QCT. The oxidation peak current demonstrated low detection limits of 0.009 μM for RU and 0.003 μM for QCT with broad linear concertation of RU and QCT were 0.02 → 121.62 μM, and 0.08 → 129.8 μM, respectively. The fabricated electrode shows a higher sensitivity of 1.352 and 3.847 μA μM−1 cm−2 for RU and QCT detection. The modified CPO/SPCE offers excellent selectivity, repeatability, reproducibility, and further monitoring for RU and QCT in spiked fruit samples showing applicable recoveries. The electrochemical supercapacitor was explored using a CPO/NF electrode that revealed high specific capacitance of 680 F g−1 at 1.0 A g−1, and good stability of 89.3% capacitance retention after 10000 cycles at 6.0 A g−1.

Nitrofurantoin (NFT) is mainly used in humans for the treatment of urinary tract infections. NFT is used as feed additives in animals, due to its broad antimicrobial activity. However, it shows more side effects on human health and the environment. Therefore low-cost, portable, and rapid sensors are necessary for the detection of NFT in real samples. Herein, we successfully developed an electrochemical sensor using a glassy carbon electrode (GCE) modified with gadolinium orthoferrite (GdFeO3) decorated on reduced graphene oxide (RGO) nanocomposite for the detection of NFT. The facile hydrothermal method was used to synthesis a novel GdFeO3/RGO nanocomposite, the morphological and structural characterization was confirmed by the FESEM, HRTEM, EDX, XRD, Raman, and XPS techniques. The formation mechanism of GdFeO3/RGO nanocomposite had been discussed. The effective intercalation of the nanostructured GdFeO3 to the RGO sheets leads to the significant enhancement in physicochemical properties such as electrical conductivity, electro-active surface area, structural stability, and electrochemical activity, which was observed from the EIS and CV experimental results. The electrochemical studies established that the developed GdFeO3/RGO sensor was highly sensitive and selective to NFT. Moreover, the GdFeO3/RGO sensor exhibits good sensitivity of 4.1985 μA μM−1 cm−2, a low detection limit (LOD) of 0.0153 µM and a linear range from 0.001 to 249 µM for NFT detection under optimized experimental conditions. In addition, the investigation of storage time on the CV response of the GdFeO3/RGO sensor indicates superior stability. Owing to these extraordinary analytical advantages, the as-fabricated sensor was applied to detect the NFT levels in human urine and river water samples with satisfactory results.

Iron vanadate (FeVO4) nanostructures were prepared using controlled hydrothermal synthesis from low temperature to high temperature (90 to 180 °C). The temperature-dependent synthesis pointed that FeVO4 nanorods can be achieved with less reaction time. The as-obtained samples were characterized in detail to analyze the hydrothermal temperature effects on structural, morphological, and electrochemical properties. From the morphological results, it is observed that there is a substantial change in particle shape and size with the increase in temperature. As an outcome, the specimen synthesized at 150 °C revealed a higher specific surface area (16.11 m2 g–1) than other temperature-varied samples. Similarly, the electrical and electrochemical performance characteristics of the proposed electrodes were comparably explored through electrochemical impedance spectroscopy (EIS) and cyclic voltammogram (CV) analyses. It is ascrtained that the electrochemical activity of the catalyst is greatly influenced by the hydrothermal temperature. Under optimized voltammetric experimental conditions, the flutamide (FLT) detection current revealed a wide linear relationship in the range of 0.06 to 777.46 μM with the lowest detection limit of 0.054 μM. Furthermore, the proposed electrode displayed an excellent anti-interference ability and high reproducibility together with acceptable performance in the detection of FLT in human blood serum. The outcomes from this study will provide a path to understanding the effects of hydrothermal temperature with shorter reaction time on the crystalline structure, surface morphology, and electrocatalytic properties of iron vanadate nanostructures that are significant for countless practical applications.

In this work, zinc vanadate microstructure (Zn3(VO4)2, ZnV MS) was successfully synthesized via the sonochemical method for the determination of metronidazole (MTZ). The crystalline structure, surface morphology, and chemical composition of the prepared ZnV MS were characterized by analytical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS) analyses. The electro-kinetic properties of ZnV MS were tested using both anodic and cathodic redox couple. Furthermore, their electroanalytical behavior was successfully investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The ZnV MS displayed excellent electrocatalytic performance in the presence of MTZ than that of an unmodified electrode. Under the optimized conditions, the ZnV MS-fabricated electrode demonstrated a broad linear range from 0.05 to 1303 µM with the low detection limit of 0.009 µM (S/N = 3) and an obtained sensitivity of 0.445 µA µM–1 cm–2. Additionally, the proposed electrode was successfully applied in the detection of MTZ in milk samples with a recovery range of 92–98%.

The long-term use of the immunosuppressive drug, azathioprine (AZT), has been linked to a higher risk of certain cancers; hence, its effective detection is necessary. Recently, the use of transition metal/metal oxide-based materials has attracted intense interest in the field of electrochemistry in combination with carbon materials. Here, we fabricate and demonstrate the use of manganese oxide nanoparticle-decorated reduced graphene oxide modified screen-printed carbon electrodes (Mn2O3–rGO/SPCE) for the electrochemical determination of AZT. The structural, functional, and morphological characteristics of the composite material were evaluated using various analytical tools. The crystalline structure of the synthesized Mn2O3 nanoparticles is identified as orthorhombic with a crystallite size of 20 nm. The existence of sphere-shaped nanoparticles on the rGO sheets and the component elements are confirmed using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX). The fabricated electrode (Mn2O3–rGO/SPCE) possesses high electrical conductance, as proved by electrochemical impedance spectroscopy, with an Rct value of 90 Ω. When compared with other electrodes, the Mn2O3–rGO/SPCE has a higher conductive behavior with a wide surface area and a boosted electron transfer, which in turn promotes the effective sensing of AZT. Differential pulsed voltammetry studies (DPV) revealed that the modified electrode possesses a lower limit of detection of about 4 nM, and a sensitivity of almost 7.7 μA μM−1 cm−2, evaluated for a linear range from 0.009 μM to 573.5 μM. Repeatability and reproducibility studies exhibited a relative standard deviation (RSD) value of about 4.96% and 4.89%. Selectivity studies proved that the proposed sensor showed good selective detection in the presence of relevant interfering compounds. The fabricated Mn2O3–rGO modified SPCE would be an efficient sensor for real-time sensing of AZT because of its effective performance with human blood serum and urine samples.

In this report, cobalt(II)-doped cobalt oxide (Co–Co2O4) rose-like nanostructures were synthesized via a facile one-step ultrasonication method. The as-prepared nano Co–Co2O4 was then utilized for the sensitive quantification of the prophylactic drug furazolidone (FUZ). Various physicochemical methods, including X-ray powder diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy, were used to confirm the successful formation of the Co–Co2O4 nanostructures. The superior active surface area and larger pores of Co–Co2O4 enhance the electrocatalytic activity towards FUZ detection. The electrochemical performance of Co–Co2O4 towards FUZ was explored using the voltammetry method, with the obtained results suggesting that the proposed Co–Co2O4 sensor exhibits excellent catalytic activity towards FUZ. Under the optimized conditions, the sensor exhibits two wide linear ranges (0.05–285 μM; 285–1122.15 μM) with a low limit of detection (8 nM) and high sensitivity (2.349 μA μM−1 cm−2). Besides this, the proposed sensor exhibits high stability, reproducibility, and repeatability. Moreover, anti-interference experiments were carried out to explore the precise detection of FUZ in the presence of similar compounds.

A high-performance electrochemical sensing platform based on CuS nano-globules is efficiently developed. The CuS nano-globules are synthesized through a hydrothermal process. All the important physical characteristics of the nanomaterial such as crystal architecture, morphology, topography and composition are investigated. To better demonstrate the electrochemical sensing capability of CuS nano-globules reinforced electrodes, hydroquinone (HQE) is chosen as an analyte. Upon the electrochemical investigation, the CuS-based sensor displayed an enhanced detection limit of 0.135 μM with a linear range of 1–2287 μM. The overall sensing performance of CuS nano-globules-equipped electrode towards HQE is very impressive with good stability and reproducibility. These investigative results evidently indicate the superior electrochemical properties of CuS nano-globules and they can be highly recommended for real-time analysis.

We demonstrated a simple and more accurate electrochemical sensor for isoprenaline (ISPT) analysis in pharmaceutical substances based on manganese cobalt oxide (MnCo2O4) modified with a glassy carbon electrode (MCO/GCE). The nanomaterial was synthesized via coprecipitation approach and characterized with various methods, including FTIR, XRD, HRTEM, FESEM, and XPS. Different experimental factors concerning the electrochemical activity of the fabricated electrode have been optimized through varying pH, loading quantity, and scan rates. The present sensor displayed powerful and consistent electron mediating activity accompanied by well-separated oxidation peaks with low overpotential activation towards ISPT. MCO/GCE was effectively used for the determination of ISPT in the concentration range from 0.2 to 121 μM with the sensitivity of 10.01 μA μM−1 cm−2, and the detection limit was 0.005 μM by differential pulse voltammetry. Surprisingly, the suggested electrode shows good reproducibility, repeatability, selectivity, and stability. Standard addition findings revealed the promising potential of MCO/GCE as an effective catalyst for the determination of ISPT in human urine and serum samples with acceptable recovery values attained at 99 to 101.2%.

Simple chemical synthesis is highly efficient to develop metal oxide composites as active electrode materials for an electrochemical sensor displaying enhanced catalytic sites, fast kinetics, and easy accessibility to target molecules. In this work, a cobalt oxide/tin oxide (Co3O4/SnO2) composite was prepared by a facile co-precipitation method and employed for the voltammetric determination of ornidazole (ODZ). The structural and morphological properties of the as-synthesized materials were studied through XRD, FT-IR, BET, FE-SEM, TEM, and XPS analyses. The electrochemical activity was investigated using cyclic voltammetric (CV) and linear sweep voltammetric (LSV) techniques. The electrochemical signal shows that the modified glassy carbon electrode (Co3O4/SnO2/GCE) revealed superior sensing ability in rapid ODZ detection compared to a single component of Co3O4 or SnO2. The performance was investigated over a wide linear range of 0.2 to 1185.8 μM with a low detection limit of 0.059 μM for ODZ, respectively, at a low-cost Co3O4/SnO2 modified electrode. Good selectivity was observed in the presence of NFT, 2-NA, and Cd2+ by the ODZ sensor. Furthermore, the excellent stability, repeatability, and reproducibility suggest that the constructed electrode based on Co3O4/SnO2/GCE is promising for real-time application in water samples.

In this study, silver nanoparticle embedded on guar gum (AgNP/GG) nanocomposite was synthesized thoroughly in greenway via a simple in situ method by silver salt reduction using the guar gum (GG) polymer matrix. The highly water-soluble polysaccharide material (GG) was served as both stabilizing and reducing agent. Its structure and morphology were characterized by XRD, FT-IR, TEM, and UV−Vis spectroscopy. EIS, CV, and DPV methods have also been employed to investigate the electrochemical performance of the AgNP/GG nanocomposite. Analytical parameters such as loading amount of catalyst, scan rate, pH value, cyclic stability, repeatability, and reproducibility were optimized. The AgNP/GG/SPCE shows a distinct electrocatalytic oxidation of diphenylamine (DPA) in a wide linear range (WLR) of 0.01−9.09 µM, a higher sensitivity of 6.879 µM cm−2, and a limit of detection (LoD) of 5.4 nM (S/N = 3). The fabricated electrode exhibits an outstanding electrocatalytic performance in terms of good reproducibility, high stability, and acceptable anti-interference ability. In addition, this work advances the feasibility to determine DPA in apple juice sample with satisfactory recovery results.

A cerium vanadium oxide decorated sulfur doped-reduced graphene oxide (CVO@SRG) nanocomposite was prepared by a modest hydrothermal method and investigated for the voltammetric measurement of an organic compound, sulfasalazine (SSZ), which has been selected for its importance as a pharmaceutical product. The as-synthesized CVO@SRG was characterized by electron microscopy and spectroscopy analyses for its structure and formation. A CVO@SRG modified disposable screen-printed carbon electrode (SPCE) as an electrocatalytic SSZ sensor exhibited an improved oxidation current at a lower oxidation potential compared to the unmodified electrode and SRG/SPCE. Under optimum conditions, the electrochemical studies of CVO@SRG/SPCE revealed a wide linear range from 0.005 to 284.6 μM with a lower limit of detection in the nanomolar range (1.2 nM) and a higher sensitivity (90.55 μA μM−1 cm−2) towards SSZ. The critical practicability of the newly made sensor was examined, and it demonstrated admirable selectivity, repeatability, and reproducibility. Furthermore, the sensor was used to sense SSZ in both serum and urine samples, which proves the potential of CVO@SRG/SPCE for practical applicability.

In this work, Ni-doped ZrO2 nanoparticles (NPs) were used to decorate multi-walled carbon nanotubes (MWCNTs) to obtain a Ni-ZrO2/MWCNT nanocomposite, which acted as an efficient electrode material for the highly sensitive electrochemical detection of the anti-inflammatory drug 5-amino salicylic acid (5-ASA). The Ni-ZrO2 NPs were obtained through a facile co-precipitation method, and the subsequent support of these Ni-ZrO2 NPs onto MWCNTs was accomplished via an ultrasonication technique. Supporting Ni-ZrO2 NPs on MWCNTs not only results in excellent catalytic properties, but it also substantially enhances the surface area, electrical conductivity, and electron transfer process. The electrochemical activity of the synthesized Ni-ZrO2/MWCNT nanocomposite was systematically investigated via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The constructed Ni-ZrO2/MWCNT-modified glassy carbon (GC) electrode manifests superior electrocatalytic oxidation activity toward 5-ASA, with a lower peak potential compared with Ni-ZrO2-NP- and MWCNT-modified GC electrodes. Importantly, the proposed biosensor exhibited excellent sensitivity during the detection of 5-ASA with a wide linear concentration range (0.001-500 μM) and a low detection limit of 0.0029 μM. Moreover, the biosensor demonstrated excellent repeatability, reproducibility, stability, and high specificity toward 5-ASA detection in the presence of different interfering species. Furthermore, the biosensor showed satisfactory recovery rates in complex biological samples, such as human blood serum, human urine, and 5-ASA tablet samples.

In this work, ultrafine rhenium–ruthenium nanoparticles decorated on functionalized multiwalled carbon nanotubes (Re-Ru@f-MWCNT) were used as a new electrode platform for simultaneous electrochemical detection of nitrofurantoin (NFT, antibiotic) and flutamide (FLT, anti-testosterone) drugs. The as-prepared composite was scrutinized using various techniques, including XRD, BET, FE-SEM, FE-TEM-EDS, XPS, elemental mapping, and Raman spectroscopy. FE-TEM results revealed that Re NP (size, 1.5–2.8 ± 0.1 nm) and Ru NP (size, 1.8 ± 0.2 nm) were well-decorated on f-MWCNT. The nanocomposite was fabricated on a glassy carbon electrode (GCE) that demonstrated superior voltammetric sensing towards NFT and FLT at pH 7.0. Interestingly, Re-Ru@f-MWCNT/GCE received two linear ranges, the limit of detection, with excellent sensitivity for NFT and FLT. Also, excellent selectivity for both individual and simultaneous detection of NFT and FLT was obtained in the presence of various potential interferences. Moreover, the fabricated sensor was studied to determine NFT and FLT levels in human urine and serum with the results showing good recoveries.

Herein, we report a simple strategy to modify kaolin clay with carbon as an electrocatalyst for quercetin detection. The modified clay composite was characterized using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was used to analyze the electron transfer process of the carbon-modified electrode. The electro-oxidation behavior of quercetin was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV experiments displayed that the electro-oxidation behavior of C-kaolin composite was significantly enhanced than unmodified kaolin clay. Under the optimized conditions, the prepared sensor showed increasing linear concentration in the range from 0.12 to 182.1 µM with the detection limit (LoD) of 0.057 µM (S/N = 3). The proposed sensor was applied for the detection of QCN in apple juice and the recovery percentage was found to be 93 to 97%. Thus, the proposed sensor is simple, cost-effective, and can be utilized for several analytical applications.

Nanostructured binary metal sulfides are considered as a promising electrode material because of their excellent electron transfer and good sensing behavior rather than metal oxides. As a result, the binary metal sulfides were applied in energy and electrochemical sensor applications. Herein, we propose the electrochemical sensor method based on flower-like cerium-ruthenium sulfide nanostructure (Ce–Ru–S NS) for the electrochemical sensing of trifluoperazine (TFPZ). The Ce–Ru–S NS prepared using the cost-effective one-pot hydrothermal synthesis technique. Then, the resultant materials were characterized through suitable spectrophotometric techniques and the electrocatalytic properties of the fabricated sensor were investigated by EIS, CV, and amperometric (i–t) techniques. The Ce–Ru–S material has good electrocatalytic activity towards the electrochemical oxidation of TFPZ. Significantly, the fabricated sensor demonstrates the distinct amperometric response with the lowest limit of detection (LOD) of 0.322 nM (S/N = 3), high sensitivity 2.682 μA μM−1 cm−2 and lowest oxidation potential of +0.64 V (Ag/AgCl). Furthermore, the Ce–Ru–S NS displays excellent selectivity, good reproducibility, and long-term stability. The practicability of the TFPZ sensor tested in a human urine sample.

We demonstrate the simply prepared Co3O4 microsphere-decorated graphene oxide nanosheets (Co3O4/GO) modified electrode towards the single and simultaneous determination of dopamine (DA) and uric acid (UA). Various analytical techniques characterized the physicochemical properties of Co3O4/GO hybrid composite and EIS, CV, and DPV used to analyze the electrochemical characterization. This result indicates the simply prepared hybrid composite was confirmed the formation of Co3O4 has a spherical shape with an anchored surface of GO nanosheets. The proposed sensor has good electron transfer properties and excellent cycling stability. The detection potential difference between DA and UA is + 0.216 V. The electrooxidation response of modified electrode exhibits a wide linear range of DA and UA concentration from 0.2 → 1221 and 0.04 → 1217.2 µM with low detection limits of 0.0874 µM and 0.0131 µM, respectively. Besides, the fabricated sensor has high selectivity, excellent storage stability, reproducibility, and repeatability. Finally, the practical applicability of the contracted sensor was evaluated individual and simultaneous detection of DA and UA in human urine samples with satisfactory results.

In this work, a graphene oxide (GRO)-based temperature-sensitive smart catalytic support material was developed by tethering biodegradable and hydrophilic poly(N-vinylcaprolactam) (PVCL) on a GRO (i.e., GRO-PVCL) surface. GRO-PVCL-supported palladium catalyst (i.e., Pd/GRO-PVCL) was then prepared for tizanidine (TZN) electroreduction. The impact of a temperature-sensitive smart surface on the electrochemical and electrocatalytic properties was examined. Moreover, when the large surface area, excellent electron transfer, and electrochemical catalysis abilities of GRO were combined with the responsive characteristics of PVCL, temperature-triggered reversible electrocatalysis of TZN with enhanced sensitivity has been proved. Results designated that GRO-PVCL exposed the hydrophilic surface at 20 °C, resulting in Pd NPs highly dispersed on the GRO-PVCL surface. Subsequently, the wettability of the Pd catalyst surface arbitrarily adapted to hydrophobicity at 40 °C, which highly enhanced the TZN reduction on the catalyst in electrochemical detection. The synergistic effect amid Pd and GRO-PVCL on Pd/GRO-PVCL improved the electrocatalytic activity of TZN. The detection of TZN with the Pd/GRO-PVCL modified electrode ranged from 0.02 to 276 μM with a low detection limit of 0.0015 μM at 40 °C. The Pd/GRO-PVCL modified electrode also possesses excellent stability, reproducibility, and anti-interference ability. Lastly, the modified electrode attained good recovery results in human urine and human plasma samples for the determination of TZN and also pharmacokinetics study in rat plasma.

In this work, we developed cerium oxide/tin oxide (CeO2/SnO2) nanocatalyst with the assistance of urea by a simple sonochemical method and utilized as an efficient electrode material for electrochemical sensing of anti-inflammatory drug 5-aminosalicylic acid (Mesalamine, MES). The CeO2/SnO2 nanoparticles (NPs) were systematically characterized in terms of their crystal structure, morphologies, and physicochemical properties using XRD, Raman, FESEM, HR-TEM, EDX, mapping, and XPS analysis. The characterization results clearly confirmed that the prepared NPs was formed in the phase of CeO2/SnO2 without any other impurities. The electrochemical properties of CeO2/SnO2 NPs were investigated by EIS, CV, and DPV techniques. The CeO2/SnO2 NPs (9.6 μA) modified GCE demonstrated an excellent and improved electrocatalytic activity in terms of higher anodic peak current and lower peak potential when compared to bare GCE (6.7 μA) and CeO2 NPs/GCE (8.2 μA) for the sensing of MES. The CeO2/SnO2 NPs/GCE shows broader linear response range and lower detection limit of 0.02–1572 μM and 0.006 μM, respectively. Moreover, other potentially interfering compounds such as a similar functional group containing biological substances and inorganic species have no interference effect towards MES sensing. In addition, the practicability of the CeO2/SnO2 NPs/GCE was tested by real sample analysis in commercial MES tablet, human urine, and serum samples with the appreciable recovery results.

The exploration of novel and proficient materials through simple, large-scale and green synthesis routes for the detection of precise levels of organophosphate insecticides in real physical systems of soil and water is a predominant concern of researchers. In light of this, we introduced a sensitive and eminently selective electrochemical sensor probe for oxyparathion (OP) based on sonochemically designed 2D samarium molybdate nanoplatelets (γ-Sm3(MoO4)3; SmM NPs). The sonochemically synthesized SmM NP catalyst was systematically investigated with respect to the crystal structure, textural morphologies, and physicochemical characteristics by XRD, Raman, FE-SEM, HR-TEM, and XPS analysis. The fabricated electrode was employed for detection and determination through different voltammetric techniques. The SmM NP fashioned screen-printed carbon electrode (SmM NPs/SPCE) demonstrated potentially superior electrocatalytic activity towards OP detection with a lower detection limit, widespread linear amplitude range and good sensitivity of 0.002 μM, 0.01–692 μM, and 0.54 μA μM−1 cm−2, correspondingly. Moreover, other interfering materials, such as inorganic species, biological compounds and nitro-group-containing OPPTs and drugs, have no influence on the detection of OP. Besides, SmM NPs/SPCE has also been utilized for OP detection in soil and actual groundwater samples and displayed excellent sensing abilities.

The accurate detection of hazardous 4-nitrophenol (4-NP) is deemed essential for the environment and human health. Exploring efficient and low-cost methods for its monitoring has become completely necessary in the current century. Herein, the high-level sensing behavior of a graphene oxide–TiO2 composite for the detection of hazardous 4-NP, using a simple electrochemical sensor technique, is reported. The hybrid electrocatalyst of graphene oxide–TiO2 composite material was prepared via an ultrasound assisted sonication method. The structural and physiochemical properties were determined in detail using PXRD, TEM, HR-TEM, Raman, FTIR, XPS, UV-DRS and BET isotherm studies. The graphene oxide–TiO2 composite shows superior electrocatalytic performance for the detection of 4-NP with high sensitivity (3.9831 μA μM−1 cm−1) coupled with a low limit of detection (LOD) and limit of quantification (LOQ), which were found to be 0.0039 μM and 0.0131 μM, respectively. This study offers an excellent platform for exploring graphene oxide–TiO2 composite materials with great potential for monitoring hazardous environmental pollutants.

The simple and novel surfactant-free synthesis of flower-like strontium-doped nickel oxide nanorods (SNO NRs) via a simple sonochemical co-precipitation method was used for electrochemical sensing of quercetin (QCT). The structure and morphology of the as-synthesized flower-like SNO NRs were characterized using various spectroscopic techniques. Then, CV, EIS, and DPV were used to examine their electrochemical properties. The effective loading concentration, pH, scan rate and stability of the SNO NR-modified electrodes were studied. Under optimized conditions, the electrochemical detection of QCT demonstrated a low detection potential of 0.3 V (vs. Ag/AgCl), and achieved a higher oxidation peak current compared to those of other modified electrodes in PB (pH 5.0). The voltammetric current response was found to linearly increase with an increasing concentration range from 0.01–68.53 μM, along with a low detection limit of 1.98 nM, and a high sensitivity of 2.1055 μA mM cm−2. The sensor also shows good selectivity and satisfactory recovery for real sample (apple and grape juice) analysis.

In this work, lanthanum molybdate nanospheres (LMNSs) were prepared by employing a co-precipitation methodology, and their electrochemical activity against nitrofurantoin (NF) was reported. The physico-chemical nature of LMNSs, and their texture and morphology were characterized by using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, powder X-ray diffraction (PXRD) and field emission scanning electron microscopy (FE-SEM) combined with energy-dispersive X-ray spectroscopy (EDX). The electrochemical studies were performed by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The ensuing LMNSs have a fantastic active surplus area and uplifted surface volume ratio, which drives the selective and sensitive detection of NF. The as-synthesized LMNSs were coated on a screen-printed carbon electrode (SPCE) by a drop cast method, and the constructed LMNSs/SPCE acts as a potential sensing material towards the reduction of NF. Also, the designed sensor exhibits a broad linear range from 0.01 to 144 μM with a lower detection limit of 72 nM and sensitivity equivalent to 2.94 μA μM−1 cm−2 for the detection of NF. Meanwhile, the fashioned sensor has good selectivity in the presence of metal ions, biomolecules and similar nitro group containing drugs.

In this work, we synthesized strontium titanate (SrTiO3) by a simple co-precipitation technique and decorated it with graphene oxide (SrTiO3/GO) for the effective determination of neurotransmitter agent dopamine (DA). The as-synthesized SrTiO3–GO nanocomposite was orderly characterized by various microscopic and spectroscopic techniques, which revealed that the formed nanocomposite was pure with a desired morphology. A SrTiO3–GO-modified glassy carbon electrode generates high current with low peak potential compared with a bare GCE with the linear range response from 0.05 to 531 μM, and the lower detection limit is 0.01 μM with higher sensitivity. However, the modified electrode exhibited good repeatability, reproducibility, stability, and selectivity during the interference study using different metal ions and biomolecules. Finally, real sample analysis was carried out in human urine and blood serum samples to identify the practical possibilities of the synthesized composite and satisfactory recovery results were obtained.

In this study, the sensitive and selective detection of bisphenol A (BPA) was achieved using a screen-printed carbon electrode (NFO/SPCE) modified with hydrothermally synthesized NiFe2O4 nanoparticles. The crystalline structure, surface morphology and electrical conductivity of the nanoparticles were analyzed using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The as-prepared NiFe2O4 (NFO) nanoparticles exhibited a cubic crystal structure with an average crystallite size of 16 nm, as calculated using the Scherrer equation. As determined by cyclic voltammetry (CV), NFO/SPCE exhibited excellent electrochemical oxidation towards the detection of BPA. Subsequently, differential pulse voltammetry (DPV) studies revealed a rapid and stable response to the consecutive addition of BPA in a linear range of 0.02–12.5 μM with a lower limit of detection (LOD) of 6 nM, which was superior to previously reported results. In addition, the proposed method showed good stability and excellent repeatability for the determination of BPA in real samples.

The highly sensitive real-time detection of antibiotic drugs (nitrofurantoin; NFT) has drawn significant research attention due to the extensive use of antibiotics, which may cause serious threats to environment as well as living things. In this work, a novel nickel stannite (NiSnO3; NSO) nanoparticles were developed via a facile sonochemical synthetic route and used as a synergistic electrocatalyst for the electrochemical determination of NFT for the first time. The structure of the as-prepared material was scrutinized by various physicochemical techniques. The impedance analysis proves that the ionic conductivity of NSO was significantly improved by the insertion of nickel ions into the tin oxide lattice. The resultant electrocatalyst exhibits a superior electrocatalytic behavior toward NFT with a low detection limit (3 nM), broad linearity (6.6 nM–0.5 μM and 0.5–466.6 μM) and rapid response (2 s) due to the increased number of active sites and the synergistic effect of NSO. In addition, the NSO nanoparticles showed excellent selectivity over the various possible interferents, good operational stability, adequate reproducibility and repeatability towards NFT detection. Besides, the practical feasibility of developed NFT sensor based on NSO was successfully investigated by applying the sensor for the monitoring of NFT in real water and biological samples with acceptable results. Hence, the developed NSO nanoparticles could serve as an auspicious electrode modifier in the field of electrochemical sensors.

In this article, an ultra sensitive and selective electrochemical sensor for the detection of Rizatriptan benzoate (RZB) was reported. The rationally designed transition metal oxides (specifically: Co and Mn) have been synthesized using a facile one-step hydrothermal method. The structural and electroanalytical properties of the prepared transition metal oxide (TMO) microstructures were examined using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and differential pluse voltammetry (DPV). The prepared microstructures such as Co3O4 polyhedrons (PHs), Mn3O4 microcubes (MCs), MnCo2O4 micro flowers (MFs) and CoMn2O4 hollow microspheres (HMs) were employed for the quantification of triptan drug Rizatriptan benzoate (RZB). As the results show, the CoMn2O4 HM modified glassy carbon electrode shows an excellent oxidation curve for the detection of RZB, which also retains a wider linear range of 0.015–2.35 μM, and 11.62–732.12 μM, with the minimum detection limit of 8.19 nM. The viability of the sensor fabrication has also been reviewed on a pharmaceutical sample (Maxalt™ oral tablets) and a biotic substance (blood serum), and considerable spike recoveries were also obtained.

In this work, gold nanoparticle (Au NP) decorated poly(diallyldimethylammonium chloride) (PDDA) functionalized graphene hydrogel (Au NP@PDDA/GH) nanocomposites were fabricated. The resulting materials were characterized by a variety of analytical and spectroscopic techniques. Electrochemical performances of the prepared composites were examined by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The Au NPs were decorated uniformly and densely on the GO@PDDA composite material based on the electrostatic attraction and this new hierarchical nanostructure can provide a more favourable microenvironment for electron transfer. Under the optimized conditions, the Au NP@PDDA/GH nanocomposite was used as a novel sensing probe for metronidazole (MZ) which was found to have the concentration range of 0.4–656.4 μM with a correlation coefficient (0.999, limit of detection (LOD) based on (LOD = 3k/∂) of 0.097 μM), and a sensitivity of 4.286 μA μM−1. With satisfactory selectivity, reproducibility, and stability, the nanostructure we proposed offered an alternative for electrode fabrication and MZ sensing. Au NP@PDDA/GH was also applied to the reduction of MZ and pharmacy tablets by NaBH4 under ambient conditions. Thus, Au NP@PDDA/GH application provides simplicity, reliability, durability, and low cost benefits.

This work focuses on the synthesis of hydroxide perovskite-based CoSn(OH)6 nanocubes (CSO NCs) by a simple co-precipitation method towards the rapid detection of rutin. The as-prepared CSO NCs were confirmed and characterized by instrumental techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), and field emission scanning electron microscopy (FE-SEM). Examination of the electrochemical properties including different pH levels, effect of loading, scan rate, interference, and stability of the rutin on the CSO NCs modified electrode was carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), respectively. Under optimal conditions, the CSO NCs modified electrode exhibits rapid sensing of rutin and delivers an ideal linear range from 0.04 μM to 15 μM which assists the minimal detection limit (LOD) of 13 nM. The proposed sensor predicts long storage stability, good selectivity, reproducibility and satisfactory recovery in orange, apple and grape juice for the determination of rutin. Therefore, the present work provides a new way to extend analytical applications in the electrochemical sensor field.

Transition metal-doped metal oxides with a typical spinal structure are considered to be the most promising electrodes for superior electrochemical sensors because of their better electrochemical conductivity and electron transfer properties than those of individual metal oxides. Here, we demonstrated the simple preparation of spinel-type zinc cobaltate nanosheets through the polyol method for the electrochemical determination of nitrofurantoin. Various spectroscopic techniques were used to characterize the as-synthesized material, and electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry techniques were used to study the electrochemical properties. The electrochemical detection of nitrofurantoin was performed based on the fabricated electrode, generating outstanding electrocatalytic performance with a limit of detection of 0.013 μM and excellent sensitivity of 2.866 μA μM−1. Moreover, the modified electrode exhibits excellent selectivity and good recoveries in real sample analysis towards the detection of nitrofurantoin.

Benefiting from the rich redox chemistry, high electrical conductivity and synergistic effect from two metal ions, the binary metal sulphides received tremendous attention in various applications. As a result, the MoS2–RuS2 nanomaterial was synthesized through the simple one-pot hydrothermal technique. The electrocatalytic activity of the as-synthesized nanomaterial was exploited towards the electrochemical detection of antibiotic drug sulphadiazine (SDZ). The electrocatalytic oxidation of the SDZ exhibited lowest anodic peak potential and ehanced anodic peak current rather than other modified electrodes. Notably, an excellent electrochemical performance with very lowest limit of detection (LOD) of 0.004 μM, appreciable linear range from 0.01 μM to 598.7 μM and high sensitivity (2.333 μA μM−1 cm−2) was obtained at MoS2–RuS2 modified electrode. Moreover, well anti-interfering property, good operational stability, repeatability and reproducibility was achieved. Facinatingly, the practicability of the modified electrode demonstrated in milk and human serum samples.

We demonstrate the different types of synthesis processes (hydrothermal, microwave and simple chemical synthesis) to prepare the Fe doped molybdenum diselenides (H-FeMoSe2, M-FeMoSe2, and C-FeMoSe2) and investigate their relevant electrocatalytic activities. The Fe doped MoSe2 exhibited an enhanced charge transfer conductivity and electrocatalytic activity. Especially, the H-FeMoSe2 with vertically aligned structures facilitate the abundant exposed active edge sites. Thus, H-FeMoSe2 modified screen-printed carbon electrode (H-FeMoSe2/SPCE) exhibited the lower Rct and better active surface area than that of M-FeMoSe2/SPCE and C-FeMoSe2/SPCE. As well as, the electrochemical sensing of mesalamine (MES) at H-FeMoSe2/SPCE is comparatively 0.46 and 1.28 fold higher than that obtained at M-FeMoSe2/SPCE and C-FeMoSe2/SPCE respectively. Thus, H-FeMoSe2/SPCE was concluded as an excellent electrocatalyst for sensing of MES and performed DPV technique. As the results, very low detection limit (0.8 nM) of MES was achieved at H-FeMoSe2/SPCE. Hence, the selected H-FeMoSe2/SPCE was successfully subjected to the real-time detection of MES by using a paramedical tablet and reported the excellent recovery range.

The frequent occurrence of furazolidone (FZD) in environmental fluids reveals the ongoing increase in use and raises concerns about the need of monitoring it. To investigate the electrochemical behavior of FZD, a novel sensor of manganese molybdenum oxide (MMO) micro rods adorned three-dimensional porous carbon (PC) electrocatalyst was constructed. The crystalline structure and surface morphology of the MMO/PC composite was characterized by XRD, Raman, FESEM, and HR-TEM. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and amperometric(i-t) methods were used to assess the electrocatalytic activity of modified electrodes. In the presence of FZD, the as-fabricated MMO/PC modified glassy carbon electrode (GCE) performed better at lower potentials with a greater peak current than other modified GCE. These results emanate from the synergistic effect of the MMO/PC suspension on the GCE. The electrochemical behavior of the amperometric(i-t) technique was used to determine FZD. Amperometric(i-t) detection yielded linear dynamic ranges of 150 nM to 41.05 µM and 41.05 to 471.05 µM with detection limits of 30 nM. The MMO/PC hybrid sensor was also effectively used to detect FZD in environmental fluids, yielding ultra-trace level detection.

Selective and sensitive dopamine (DPA) sensor was developed using hydrothermally prepared functionalized multi-walled carbon nanotube–coated bismuth molybdate (f-MWCNT@BMO). The f-MWCNT@BMO-reinforced electrode exhibited an outstanding electrocatalytic activity towards DPA oxidation. The nanocomposite-reinforced electrode displayed a rapid response towards DPA sensing and possessed the minimized potential of (Epa + 0.285 V vs Ag/AgCl) in 0.1 M phosphate buffer (PB). The electrochemical results of prepared sensors were analyzed using the differential pulse voltammetry method (DPV). As a result, the f-MWCNT@BMO-reinforced electrode exhibited a widelinear range of 10 nM - 814 μM with a very low detection limit of 3.4 nM towards DPA oxidation. The developed sensor shows excellent selectivity in presence of similar functional group biomolecules. The detection of DPA in real samples was evaluated in human serum, as the results of the proposed sensor possessed good recoveries.

The highly selective and sensitive electrochemical detection of highly toxic fungicide carbendazim (CBZ) by the iron (Fe)-doped copper vanadate (CuVO4; CuV) is discussed. The Fe-doped copper vanadate (Fe-CuV) is prepared by the simple co-precipitation method followed by an annealing process which produced high crystallinity. The material properties of Fe-CuV are characterized by XRD, Raman spectrometry, XPS analysis, HRTEM, and SAED pattern. The electrochemical characterization of Fe-CuV towards CBZ detection are done by CV and DPV techniques. The Fe-CuV/GCE exhibits good electroanalytical activity towards the electro-oxidation of CBZ at the potential of 0.81 V vs Ag/AgCl. The developed sensor electrode revealed a linear range of 0.01 to 83.1 μM and a limit of detection of about 5 nM. In addition, Fe-CuV/GCE reveals good storage stability (RSD = 2.63%) and reproducibility (RSD = 2.85%) for the electro-oxidation of CBZ. The electrode material was applied to the detection of CBZ in apple juice and soy milk samples, and the results were discussed. Thus, our projected Fe-CuV/GCE can be employed as electrode material in a rapid onsite sensor for the detection and determination of noxious pollutants.

Herein, a novel Zinc Ferrite nanocubes (ZnFe2O4 NCs) decorated reduced graphene oxide (rGO) nanocomposite have been designed through a sonochemical method. After then, as-synthesized ZnFe2O4 NCs/rGO was characterized by XPS, XRD, HRTEM and EIS. Furthermore, the ZnFe2O4 NCs/rGO nanocomposite modified GCE (glassy carbon electrode) shows excellent electrochemical sensing performance towards biomarker of 4-nitroquinoline N-oxide (4-NQ) with fast detection. 4-NQ is one of the important cancer biomarker. Moreover, the fabricated sensor showed a wide linear window for 4-NQ between 0.025 and 534.12 µM and nanomolar detection limit (8.27 nM). Further, the as-prepared ZnFe2O4 NCs/rGO/GCE has been applied to the determination of 4-NQ in human blood and urine samples with excellent recovery results.

4-Nitroquinoline N-oxide (4-NQO) is an important tumorigenic organic compound with high adverse effect in the human body. In this study, a novel Bismuth Tungstate nanospheres (Bi2WO6) decorated reduced graphene oxide (Bi2WO6/rGOS) nanocomposite have been designed through a sonochemical method. The as-synthesized Bi2WO6/rGOS was characterized through the HRTEM, FESEM, XPS, EIS and XRD. Furthermore, the nanocomposite modified glassy carbon electrode (GCE) was developed for the determination of 4-NQO. The results showed that the Bi2WO6/rGOS nanocomposite modified electrode exhibit valuable responses and excellent electrocatalytic activity. The fabricated sensor was facilitated the analysis of 4-NQO with a nanomolar detection limit (6.11 nM). Further, the as-synthesized Bi2WO6/rGOS modified electrode has been applied to sensing of 4-NQO in human blood and urine samples with satisfactory recovery.

To dates, the facile synthesis of inorganic–coated organic polymer composite has received greater attention in the order of research fields including advanced materials and electrochemical analysis owing to the complementary or synergistic effects. In this context, Pr2O3 and Pr2O3 coated polystyrene (Pr2O3/PS) inorganic–organic colloidal composite were prepared via ultrasound-induced radicals initiated precipitation and dispersion polymerization methods. The synthesized Pr2O3/PS composite was systematically studied by FE-SEM, TEM, EDX, FT-IR, XRD, and XPS analysis. This composite modified glassy carbon electrode (Pr2O3/PS GCE) was utilized to construct a novel electrochemical sensor for the detection assay of chemotherapy agent methotrexate (MTA). Under optimal condition, the designed sensor showed outstanding performance for MTA trace level detection over the linear concentration range of 0.01–236 µM with a detection limit of 0.8 nM for MTA. Furthermore, the prepared sensor accomplished excellent stability and relevant reproducibility, in addition to reliable practical assay in real human blood serum and urine samples. Besides, the possible MTA sensing mechanism of Pr2O3/PS GCE has been deliberated in detail. Our finding suggested that the developed Pr2O3/PS composite might be a favorable material for the fabrication of the high-performance electrochemical sensor.

Herein, novel manganese sulfide nanoparticles (MnS NPs) decorated reduced graphene oxide (rGOS) nanocomposite have been designed through a facile ultrasound-assisted method and followed by a sonication process. After then, as-synthesized α-MnS@rGOS was characterized by HRTEM, FESEM, XPS, XRD and EIS. Furthermore, the α-MnS@rGOS nanocomposite modified SPCE (screen-printed carbon electrode) shows excellent electrochemical sensing performance towards Parkinson’s disease biomarker of dopamine (DA). Moreover, the fabricated sensor showed a wide linear range for dopamine between 0.02 and 438.6 µM and nanomolar detection limit (3.5 nM). In addition, the α-MnS@rGOS modified SPCE showed selectivity towards the detection of dopamine in presence of a 10-fold higher concentration of other important biomolecules. The nanocomposite film modified SPCE sensor was good stable and reproducible towards the detection of Parkinson's disease biomarker. Furthermore, the as-synthesized α-MnS@rGOS nanocomposite modified SPCE has been applied to the determination of dopamine in human serum, rat serum and pharmaceutical samples with acceptable recoveries.

An electrochemical sensor based on a glassy carbon electrode (GCE) modified by three-dimensional graphene (3D-GE) and polyglutamic acid (PGA) was developed to quantitatively detect Amoxicillin (AMX), a worldwide used antibiotic. AMX response at PGA/3D-GE/GCE involving the transfer of one electron and an equal number of protons were determined using electrochemical approaches. Density functional theory simulations were performed to give insights on the reaction mechanism of AMX on the surface of the modified electrode. When the optimization of the experimental conditions was completed, the linear range of AMX was 2–60 μM. Besides, the detection limit was calculated as 0.118 μM (S/N = 3). And the modified electrode could detect the concentration of the AMX in human urine samples. Overall, the developed PGA/3D-GE/GCE for determination of AMX shows great potentials in practice.

Herein, a novel iron nitride nanoparticles (Fe2N NPs) decorated reduced graphene oxide (rGOS) nanocomposite have been designed through a solvothermal method and followed by a nitridation process. After then, as-synthesized Fe2N NPs@rGOS was characterized by HRTEM, FESEM, XPS, XRD, and EIS. Furthermore, the nanocomposite modified SPCE (screen-printed carbon electrode) shows excellent electrochemical sensing performance towards biomarker of 4-nitroquinoline N-oxide (4-NQO) with fast detection. 4-NQO is one of the important cancer biomarker. Moreover, the fabricated sensor showed a wide linear window for 4-NQO between 0.05–574.2 μM and nanomolar detection limit (9.24 nM). Further, the as-prepared Fe2N NPs@rGOS/SPCE has been applied to the determination of 4-NQO in human blood and urine samples with recoveries close to 100%.

The present work reports the facile and cost-effective synthesis of rod like structured nickel doped bismuth sulphide (Ni-Bi2S3) via the ultrasonication process. The sonochemical synthesis technique is rapid, simple, non-explosive, and harmless than other conventional synthesis technique. After the synthesis, the resultant material was characterized through the various spectrophotometric techniques including FESEM, EDX, XRD, XPS and EIS. After the structural evaluation, as-synthesized Ni-Bi2S3 was applied for the electrocatalytic detection of promethazine hydrochloride (PMTZ) using CV and amperometry (i-t) techniques. Captivatingly, excellent electrocatalytic performance with the wider linear range from 1 nM to 163.17 µM was obtained for the electrochemical determination of PMTZ. The limit of detection (LOD) and sensitivity calculated around 0.4 nM and 2.904 μA µM−1 cm−2, respectively. Besides, an excellent selectivity, satisfactory reproducibility and good stability of the Ni-Bi2S3 modified electrode were checked towards the electrochemical determination of PMTZ. Furthermore, the real time application of PMTZ sensor was established in human serum and urine samples.

In this paper, mesoporous tungsten sulfide electrocatalyst (MP-WS2) were developed through a facile sonochemical technique (SC) and utilized as an electrocatalyst for the sensitive electrochemical detection of Psychoactive drug. The as-prepared SC-MP-WS2 NRs and HT-WS2 NPs (hydrothermally synthesized) were characterized using XRD, Raman, XPS, FESEM, HRTEM, BET, EDX, and electrochemical analysis, which exposed the formation of WS2 in the form of mesoporous nanorods in shape. Further, the use of the as-developed SC-MP-WS2 NRs and HT-WS2 NPs as an electrocatalyst for the detection of clonazepam (CNP). Interestingly, the SC-MP-WS2 NRs modified screen-printed carbon electrode (SC-MP-WS2 NRs/SPCE) exhibited an excellent electrocatalytic performance, and enhanced reduction peak current when compared to HT-WS2 NPs with unmodified electrode. Moreover, as-prepared SC-MP-WS2 NRs/SPCE displayed wide linear response range (10–551 µM), lower detection limit (2.37 nM) and high sensitivity (24.32 µAµM–1cm−2). Furthermore, SC-MP-WS2 NRs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds. The proposed sensor was successfully applied for the determination of CNP in biological and drug samples with acceptable recovery.

A simple, novel electrochemical sensing platform based on porous g-C3N4 (PCN) and multi-walled carbon nanotubes (MWCNTs) for the sensitive detection of uric acid (UA) has been proposed. The obtained PCN possessed good biocompatibility and large specific surface area with good dispersion, which was beneficial to electrocatalysis. The introduction of MWCNT as the conducting matrix improved the poor conductivity of PCN. Due to synergistic effect, the redox peak currents of UA substantially enhanced at PCN/MWCNT-modified electrode. The oxidation peak current exhibited linear responses to the concentration of UA in the range from 0.2 to 4 μM and 4 to 20 μM, and the limit of detection was calculated as 0.139 μM (signal-to-noise ratio of 3 (S/N = 3)). The sensor based on PCN/MWCNT-modified electrode was also successfully applied in human serums and also showed excellent selectivity, reproducibility, and stability. This work illustrated that the fabricated electrochemical sensor was promising for analytical applications.

A sensitive and selective amperometric detection of hydrogen peroxide (H2O2) sensor in biological samples was developed using platinum nanoparticles decorated graphite/gelatin hydrogel (PtNPs@GR/GLN) composite. The GLN hydrogel taking an advantage of dispersing medium as well as supporting agent for selectively welcomes H2O2 molecule on the electrode surface. The PtNPs@GR/GLN composite was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. The number of PtNPs deposition cycles, effect of scan rate and solution pH were studied and discussed in details. The electrochemical behavior of PtNPs@GR/GLN modified electrode was investigated by cyclic voltammetry (CV) and showed an excellent electrocatalytic activity and lower detection potential towards the sensing of H2O2. Besides, the amperometric i-t curves displayed a fast diffusion and wide linear response range of H2O2 concentrations from 0.05 to 870.6 μM with a detection limit (LOD) of 37 nM. The PtNPs@GR/GLN modified electrode exhibited selectively detect H2O2 molecule in presence of biologically active interfering molecules. The PtNPs@GR/GLN modified electrode was successfully applied for the determination of H2O2 in biological real samples such as human serum and saliva for practical applications.

However the usage of insecticides are essential to safeguard the crops, the increase in its permissible levels imposes several health issues. The organophosphate insecticides like fenitrothion (FNT) are known for its rapid migration properties and adverse health effects. Therefore, precisely detecting the dissemination of FNT in ecology is very much essential. In this article, we reported a synthetic approach to rGO-Tungsten carbide nano-polyhedrons (rGO-WC NPHs) composite. Then economically, rGO-WC NPHs were fabricated on the screen-printed carbon electrode (SPCE) for the determination of FNT in environmental water and forest soil samples. As expected its shows moral analytical parameters, such as wider linear range of 10 nM–471.2 μM, with the very low detection limit of 1.15 nM. The sensitivity possessed by the prepared robust FNT detector is 5.3760 μAμM−1cm−2. The results acquired for the developed sensor (rGO-WC NPHs/SPCE) were also compared with the standardized HPLC method to validate the robustness of the sensor.

In this work, strontium cerate nanoparticles (SrCeO3 NPs, SC NPs) were developed through facile synthetic techniques (Ultrasound-Assisted (UA) and Stirring-Assisted (SA) synthesis) and utilized as an electrocatalyst for the selective and sensitive electrochemical detection of calcium channel blocker nifedipine (NDF). The as-prepared UASC NPs and SASC NPs were characterized using XRD, Raman, TEM, EDS, mapping, XPS and BET analysis which exposed the formation of SC NPs in the form of spherical in shape and well crystalline in nature. BET studies reveal that UASC NPs have maximum surface area than that of SASC NPs. Further, the use of the as-developed UASC NPs and SASC NPs as an electrocatalyst for the detection of NDF. Interestingly, the UASC NPs modified screen printed carbon electrode (UASC NPs/SPCE) exhibited an excellent electrocatalytic activity in terms of lower reduction potential and enhanced reduction peak current when compared to SASC NPs and unmodified SPCE. Moreover, as-prepared UASC NPs/SPCE displayed wide linear response range (LR, 0.02–174 µM), lower detection limit (LOD, 5 nM) and good sensitivity (1.31 µA µM−1 cm−2) than that of SASC NPs (LR = 0.02–157 µM, LOD = 6.4 nM, sensitivity – 1.27 µA µM−1cm−2). Furthermore, UASC NPs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds such as similar functional group containing drugs, pollutants, biological substances and some common cations/anions. The developed sensor was successfully employed for the determination of NDF in real lake water, commercial NDF tablet and urine samples with acceptable recovery.

In this study, a novel polystyrene:β-cyclodextrin inclusion complex-supported yttrium oxide (Y2O3)-modified glassy carbon electrode (PS:β-CD IC/Y2O3/GCE) was developed for the simultaneous determination of selected drugs, 4-aminoantipyrine (4-AAP) and acyclovir (ACV) for the first time. The results showed that PS:β-CD IC/Y2O3/GCE exhibits well-defined oxidation peak currents with a lower positive shift in peak potential in the simultaneous determination of 4-AAP and ACV compared to the bare GCE, demonstrating the superior catalytic activity. The fabricated sensor showed the linear ranges of 0.01–655 and 0.01–918 μM with low detection limits of 0.01 and 0.02 μM for the determination of 4-AAP and ACV, respectively. Further, the as-prepared PS:β-CD IC/Y2O3/GCE has been applied to the simultaneous and individual determination of 4-AAP and ACV in human urine and commercial ACV tablet samples with satisfactory recovery (98–99.3 and 88–96.6%), thereby showing a notable potential for extensive applications in the...

The Dopamine and Uric acid play a prominent part in mammalian neuronal networks, which bridges the brain and neurons. Accordingly, several types of research were passionate about the sensing of Dopamine (DA) and Uric acid (UA) in food and biological samples. Consequently, the sensing properties of notorious materials, ought to be elevated through the morphological tuning for the development of advanced DA and UA sensors. For the very first time, a comprehensively applied effective material of the DA and UA sensors, Zinc oxide (ZnO) is prepared through the microwave method with the different stoichiometric ratios of urea, such as [C4H6O4Zn · 2H2O: CH4N2O] = [1:1], [1:2], and [1:3], respectively. After that, we established the DA and UA biosensor over the cost-effective screen-printed carbon electrode (SPCE) adaption method. Thus, the ZnO adapted electrode exhibited excellent catalytic properties towards the simultaneous detection of DA and UA. It gained a broad working range between 100 nM and 374 μM for DA and 100 nM and 169 μM for UA with the ultralow limit of detection and significant sensitivity. This technique is effectively exploited for the detection of DA and UA levels in the samples of meat, wheat flour, and human urine.