Ti3AlC2 MAX Phase Modified Screen-Printed Electrode for the Fabrication of Hydrazine Sensor

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1-50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.

A novel colorimetric fluorescent probe for detecting hydrazine in living cells and zebrafish

Hydrazine (NH₂ NH₂ ) is a highly toxic organic substance that poses threat to human health. Monitoring hydrazine with high sensitivity and selectivity is very important. Herein, a simple colorimetric fluorescent probe for hydrazine detection, which is a seminaphthorhodafluor derivative containing thiophene-2-carboxylic acid ester reaction site, was rationally constructed. The probe itself exhibits weak fluorescence. The fluorescence is significantly enhanced when hydrazine is added. The probe exhibited a broad linear range (0-1 mM) with satisfactory selectivity and sensitivity (LOD 36.4 nM), which turns out to be an excellent fluorescent probe for monitoring hydrazine. Additionally, the probe was used to track hydrazine in living cells and zebrafish with great success, and the detection performance was satisfying. These results proved that this type of fluorescent probe with the thiophene-2-carboxylic acid ester structure can detect hydrazine with higher selectivity and sensitivity.

Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process

Herein, novel Co₃O₄·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles’ structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/μ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/μ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/μ-Chip sensor, such as excellent sensitivity (1.3842 µAµM⁻¹cm⁻²), a wide linear dynamic range of 1.0 nM–2.0 mM (R² = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/μ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

Photocatalytic, anti-bacterial performance and development of 2,4-diaminophenylhydrazine chemical sensor probe based on ternary doped Ag·SrSnO3 nanorods

Ag·SrSnO₃ NRs is an excellent photocatalyst, kills both Gram positive and Gram negative bacteria. The 2,4-DAPHyd sensor fabricated by layered Ag·SrSnO₃ NRs onto GCE shows high sensitivity (7.5854 μA μM⁻¹ cm⁻²); LDR, 0.1 nM~0.01 mM & LOD, 96.13 ± 4.81 pM.

Photocatalysis, photoinduced enhanced anti-bacterial functions and development of a selective m-tolyl hydrazine sensor based on mixed Ag·NiMn2O4 nanomaterials

In this work, a tri-metal based nanocomposite was synthesized and characterized. A detailed investigation of the photocatalytic dye degradation efficiency of the nanocomposite under visible light showed promising results in a wide pH range, both acidic and basic medium. Studies on anti-bacterial activity against seven pathogenic bacteria, including both Gram positive and Gram negative species, were conducted in the presence and absence of light and compared with the standard antibiotic gentamicin. The minimum inhibitory concentration (MIC) values of Ag·NiMn₂O₄ against multidrug-resistant (MDR) pathogens ranged from 0.008 to 0.65 μg μL^-1, while the minimum bactericidal concentration (MBC) was found to be 0.0016 μg μL^-1. The nanomaterial, Ag·NiMn₂O₄ was deposited onto the surface of a glassy carbon electrode (GCE; 0.0316 cm²) as a thin film to fabricate the chemical sensor probe. The proposed sensor showed linear current (vs. concentration) response to m-THyd (m-tolyl hydrazine) from 1.0 pM to 0.01 mM, which is denoted as the linear dynamic range (LDR). The estimated sensitivity and detection limit of the m-THyd sensor were found to be 47.275 μA μM^-1 cm^-2 and 0.97 ± 0.05 pM, respectively. As a potential sensor, it is reliable due to its good reproducibility, rapid response, higher sensitivity, working stability for long duration and efficiency in the analysis of real environmental samples.

Detection of 3,4-diaminotoluene based on Sr0.3Pb0.7TiO3/CoFe2O4 core/shell nanocomposite via an electrochemical approach

We reported a scalable sol–gel method for the preparation of Sr_0.3Pb_0.7TiO₃/CoFe₂O₄ core–shell magnetic nanocomposite with a finely controlled shell and evaluated its efficiency as an electrochemical sensor for the selective detection of 3,4-diaminotoluene.

Assessment of environmentally unsafe pollutants using facile wet-chemically prepared CeO2–ZrO2 nanocomposites by the electrochemical approach

Selective and sensitive 4-methoxyphenol chemical sensor was developed with a co-doped CeO₂–ZrO₂ nanocomposite modified glassy carbon electrode as a sensor probe by electrochemical approach for the safety of environmental and ecological fields in broad scales.

Enhanced visible light-mediated photocatalysis, antibacterial functions and fabrication of a 3-chlorophenol sensor based on ternary Ag2O·SrO·CaO

A novel multi-metal oxide nanocomposite, Ag₂O·SrO·CaO, was synthesized by a facile co-precipitation method followed by calcinations. The synthesized nanocomposite was characterized by XRD, FESEM, EDS, TEM, FTIR spectroscopy and photoluminescence (PL) spectroscopy. The composite showed enhanced photocatalytic activity under visible light irradiation and excellent anti-bacterial performance against both Gram-positive and Gram-negative bacteria. Here, the synthesized Ag₂O·SrO·CaO nanomaterials were deposited on a glassy carbon electrode (GCE) in the form of a thin film to fabricate the desired electrochemical sensor and subjected to I–V analysis of 3-chlorophenol (3-CP) in a phosphate buffer solution (PBS). A calibration curve was plotted from the linear relation of current versus concentration and used to calculate the sensitivity (8.9684 μA μM⁻¹ cm⁻²), linear dynamic range (LDR, 0.1 nM to 0.01 mM) and lower limit of detection (DL, 97.12 ± 4.86 pM). The analytical parameters of the sensor such as response time, reproducibility and long-term stability in the detection of 3-CP were reliable. Finally, it was used to analyze real samples collected from various environmental sources and found to be acceptable.

The electrochemical detection mechanism of 3-CP in PBS buffer using the heterostructure nanocomposite Ag₂O·SrO·CaO. The proposed electrochemical reaction is supposed as C₆OH₅Cl + 11H₂O → 6CO₂ + 27H⁺ + Cl⁻ + 26e⁻.

Fabrication of a hydrazine chemical sensor based on facile synthesis of doped NZO nanostructure materials

In this approach, nickel-doped zinc oxide (NZO) nanostructure materials were synthesized by the solution method in the basic phase.

3-Methoxyphenol chemical sensor fabrication with Ag2O/CB nanocomposites

The proposed chemical sensor based on Ag₂O/CB nanocomposites is developed by electrochemical approach for the detection of hazardous selective 3-methoxyphenol chemical sensor for the safety of the environment sector in a broad scale.

A non-enzymatic electrochemical approach for l-lactic acid sensor development based on CuO·MWCNT nanocomposites modified with a Nafion matrix

Copper oxide decorated multi-walled carbon nanotube nanocomposites (CuO·MWCNT NCs) were prepared using a simple wet-chemical technique in basic medium.

Simultaneous detection of l-aspartic acid and glycine using wet-chemically prepared Fe3O4@ZnO nanoparticles: real sample analysis

An easy and reliable wet-chemical method was used to synthesize iron oxide doped zinc oxide nanoparticles (Fe₃O₄@ZnO NPs) at a low-temperature under alkaline medium.

Amperometric sensing of hydrazine in environmental and biological samples by using CeO2-encapsulated gold nanoparticles on reduced graphene oxide

CeO₂-encapsulated gold nanoparticles (AuNPs) were anchored to reduced graphene oxide (RGO/Au@CeO₂) by an interfacial auto-redox reaction in a solution containing tetrachloroauric acid and Ce(III) on a solid support. The resulting material was placed on a glassy carbon electrode (GCE) and used as an electrochemical hydrazine sensor at trace levels. The electrocatalytic activity of the modified GCE towards hydrazine oxidation was significantly enhanced as compared to only RGO/CeO₂, or CeO₂-encapsulated AuNPs, or AuNPs loaded on CeO₂ modified with RGO. This enhancement is attributed to the excellent conductivity and large surface area of RGO, and the strong interaction between the reversible Ce⁴⁺/Ce³⁺ and Au^δ+/Au⁰ redox systems. The kinetics of the hydrazine oxidation was studied by electrochemical methods. The sensor, best operated at a peak voltage of 0.35 V (vs. saturated calomel electrode), had a wide linear range (that extends from 10 nM to 3 mM), a low detection limit (3.0 nM), good selectivity and good stability. It was successfully employed for the monitoring of hydrazine in spiked environmental water samples and to in-vitro tracking of hydrazine in cells with respect to its potential cytotoxicity. Graphical abstract CeO₂-encapsulated gold nanoparticles anchored on reduced graphene oxide with the strong interaction between the reversible Ce⁴⁺/Ce³⁺ and Au^δ+/Au⁰ reductions can be used for sensitive detection of hydrazine with detection limit of 3 nM and good selectivity in environmental and biological samples.

Efficient selective 4-aminophenol sensing and antibacterial activity of ternary Ag2O3·SnO2·Cr2O3 nanoparticles

The electrochemical oxidation of 4-AP based on Ag₂O₃·SnO₂·Cr₂O₃ NPs/binder/GCE sensor.

Synthesis of novel pyrazole incorporating a coumarin moiety (PC) for selective and sensitive Co2+ detection

An efficient regioselective synthesis of a novel pyrazole derivative containing a coumarin moiety was achieved, which was electrodeposited as PC/Nafion/GCE sensor probe to detect the selective Co²⁺ ions for the safety of environment and healthcare fields.

Detection of uric acid based on doped ZnO/Ag2O/Co3O4 nanoparticle loaded glassy carbon electrode

Highly sensitive and selective uric acid sensor was fabricated using facile wet-chemically prepared ternary doped ZnO/Ag₂O/Co₃O₄ nanoparticles onto glassy carbon electrode by electrochemical approach, which introduced a prospective and reliable route to the future development of enzyme-free sensor by doped nanomaterials in broad scales.

Development of 3-methoxyaniline sensor probe based on thin Ag2O@La2O3 nanosheets for environmental safety

An electrochemical sensor based on glassy carbon electrode modified by Ag₂O@La₂O₃ nanosheets with 5% ethanolic nafion as conducting binder was developed for the selective and ultra-sensitive determination of 3-methoxyanaline in the presence of other interfering toxic chemicals in aqueous system by electrochemical approach for the first time.