Hg2+ Sensor Development Based on (E)-N'-Nitrobenzylidene-Benzenesulfonohydrazide (NBBSH) Derivatives Fabricated on a Glassy Carbon Electrode with a Nafion Matrix

Sol-Gel Synthesis and Characterization of Highly Selective Poly(N-methyl pyrrole) Stannous(II)Tungstate Nano Composite for Mercury (Hg(II)) Detection

The sol-gel process was used to create a new type of polypyrrole-Stannous(II)tungstate nanocomposite by poly(N-methyl pyrrole (PNMPy) sol in Stannous(II)tungstate gel, produced separately using sodium silicotungstic acid and Tn(II)chloride. Tin(II)tungstate (SnWO3) was made by changing the mixing volume ratios of SnWO3 and with a constant amount of an organic polymer. The composite was characterized by TGA, XRD, FTIR, and SEM measurements. A commercially available glassy carbon electrode (GCE) was modified with PNMPy/nano-Stannous(II)WO3 nanocomposites to create a chemical sensor for selective detection of Hg2+ ions using an effective electrochemical methodology. In the I-V technique, selectively toxic Hg2+ ion was targeted selectively, which shows a rapid reaction toward PNMPy/nano-Stannous(II)WO3/Nafion/GCE sensor. It also demonstrates long-term stability, an ultra-low detection limit, exceptional sensitivity, and excellent reproducibility and repeatability. For 0.1 mM to 1.0 nM aqueous Hg2+ ion solution, a linear calibration plot (r2: 0.9993) was achieved, with a suitable sensitivity value of 2.8241 AM−1 cm−2 and an extraordinarily low detection limit (LOD) of 3.40.1 pM (S/N = 3). As a result, the cationic sensor modified by PNMPy/nano-Stannous(II)WO3/GCE could be a promising electrode.

Development of L-cysteine sensor based on thallium oxide coupled multi-walled carbon nanotube nanocomposites with electrochemical approach

Here, Nanocomposites of thallium oxide doped multi-walled carbon nanotube (Tl2O.MWCNT NCs) were prepared by utilizing the wet-chemical method (WCM) in an alkaline phase at low temperature. Different optical procedures (FTIR: Fourier Transform Infra-Red Spectroscopy, XRD: Powder X-ray diffraction, FESEM: Field-Emission Scanning Electron Microscopy, XEDS: X-ray Electron Dispersive Spectroscopy, TEM: Tunneling Electron Microscopy, and XPS: X-ray photoelectron spectroscopy) were used to fully characterize (Optical, structural, crystalline, morphological, and elemental etc.) of the prepared Tl2O.MWCNT NCs. Modification of the thin-layer with NCs onto glassy carbon electrode (GCE) is prepared and applied for the enzyme-free detection of selective and sensitive L-cysteine by electrochemical approach. Using a reliable current-voltage approach, analytical sensing indexes such as sensitivity, LDR, LOD, LOQ, durability, and interference were assessed by fabricated sensor probe (GCE/Tl2O.MWCNT NCs/CPM) in selective detection of L-cysteine in a room condition, whereas nafion was used as conducting polymer matrix (CPM) during the fabrication of GCE with NCs. L-cysteine calibration plot was found to be linear over an extensive range of concentration. The calibration curve was used to calculate the sensing parameters such as sensitivity (316.46 pAμM-1cm-2), LOD down to (~18.90 ± 1.89 pM), and LOQ (63.0 pM) of the prepared sensor. The use of a simple WCM to validate the Tl2O.MWCNT NCs is a good approach for developing a NCs-based sensor for enzyme-free biomolecule identification and detection in the biomedical and health care fields in a broad scale. This proposed sensor (GCE/Tl2O.MWCNT NCs/CPM) is used to detect selective L-cysteine in real biological samples such as human, mouse, and rabbit serum and found acceptable and satisfactory results.

Fluorescence-active and peroxidase-like expanded mesoporous silica-encapsulated ultrasmall Pt nanoclusters: a novel colorimetric/fluorescent dual-mode nanosensor for sensitive detection of mercury in medicinal and edible Pueraria lobata

A novel colorimetric/fluorescent dual-mode nanosensor for Hg²⁺ detection was constructed using expanded mesoporous silica (EMSN)-encapsulated ultrasmall platinum nanoclusters (EMSN@Pt NCs) with improved peroxidase-like and stable fluorescent activities. The sensing technique was based on the mechanism that the peroxidase mimetic activity and fluorescence intensity of EMSN@Pt NCs can be inhibited in the presence of Hg²⁺. In this sensing platform, a linear range of 5-50 nM with a detection limit of 1.78±0.38 nM and quantification limit of 5.93 nM was obtained via fluorescent analysis. A linear calibration curve from 0.25 to 200 nM with a detection limit of 8.25±0.51 nM and quantification limit of 27.47 nM was achieved via colorimetric analysis. The proposed dual-mode probe possesses excellent selectivity and reliability for Hg²⁺ detection, which can function as an efficient nanosensor for the quantitative determination of Hg²⁺ in Pueraria lobata.

An enzyme free simultaneous detection of γ-amino-butyric acid and testosterone based on copper oxide nanoparticles

Herein, an easy wet-chemical process was used in basic medium with low temperature to prepare low-dimensional copper oxide nanoparticles (CuO NPs). A variety of optical and structural techniques such as UV-visible, FT-IR, XRD, FESEM, XEDS, and XPS were used to characterize the synthesized CuO NPs in detail. Two sensitive and selective sensor probes for γ-amino-butyric acid (GABA) and testosterone (TST) were achieved after modification; a thin layer of NPs on a flat glassy carbon electrode (GCE). Sensor analytical parameters such as sensitivity (SNT), linear dynamic range (LDR), limit of detection (LOD), limit of quantification (LOQ), robustness, and interference effects, were evaluated for the proposed sensor (GCE/CuO NPs) for GABA and TST, based on a dependable current-voltage technique. Calibration curves were found to be linear (R ² = 0.9963 and 0.9095) over a broad concentration range of GABA and TST (100.0 pM to 100.0 mM and 10.0 pM to 10.0 mM, respectively). Sensor parameters - SNT (316.46 and 2848.10 pA μM^-1 cm^-2), LDR (100.0 nM to 10.0 mM and 10.0 pM to 1.0 mM), LOD (≈11.70 and 96.67 pM), and LOQ (39.0 and 322.2 pM) - for GABA and TST were calculated from the calibration plot successively. Preparation of CuO NPs using the wet-chemical technique is a good approach for perspective expansion of NPs-based sensors for the enzyme-free detection of biomolecules. Our sensor probe (GCE/CuO NPs) is applied for the cautious recognition of GABA and TST in real biological samples -human, mouse, and rabbit serum - and achieved good and acceptable results.

Colorimetric detection of Hg(II) by γ-aminobutyric acid-silver nanoparticles in water and the assessment of antibacterial activities

In this work, we report the synthesis of silver nanoparticles (AgNPs) via a wet-chemical reduction procedure using citrate (Cit) and γ-aminobutyric acid (GABA) as stabilizers. The formation of GABA-Cit@AgNPs was confirmed by UV-vis spectroscopy with a surface plasmon resonance band at 393 nm clearly confirming the formation of silver nanoparticles. AgNPs were characterized using UV-vis spectroscopy, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), dynamic light scattering (DLS), and zeta potential. The as-prepared AgNPs can be used for the detection of hazardous mercury ions (Hg²⁺) in water by colorimetric method with a limit of detection (LOD) and limit of quantitation (LOQ) of 2.37 μM and 3.99 μM, respectively. The linear working range for Hg²⁺ detection is 5-35 μM and the sensor probe was applied to investigate Hg²⁺ in real drinking water samples with satisfied results. Rapid response to Hg²⁺ is also observed when the nanoparticles are composited within hydrogels. Moreover, GABA-Cit@AgNPs shows antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The fast and sensitive response of the proposed Hg²⁺ sensor, together with its antibacterial activities, makes GABA-Cit@AgNPs potentially applicable for the development of cheap, portable, colorimetric sensors in fieldwork.

Synthesis and photophysical studies on a new fluorescent phenothiazine-based derivative

A new typical phenothiazine compound functionalized with thienyl-indandione derivative (PTZTID) was synthesized and characterized using spectral analysis (ultraviolet-visible (UV-vis) light, infrared (IR), ¹ H nuclear magnetic resonance (NMR) and ¹³ C NMR tools). The UV-vis absorption spectra of the PTZTID solution in 1,4-dioxane showed two absorption bands attributed to localized aromatic π-π* transitions of conjugated aromatic moieties and intramolecular charge transfer with the characteristics of a π-π* transition. The fluorescence spectra exhibited a maximum emission wavelength at 580 nm. The effect of concentration on photophysical properties took the form of a minor hypsochromic shift, which was attributed to some extent to the occurrence of H-type aggregation of the PTZTID derivative. Binary solvent effects on the spectroscopic behaviour of PTZTID were measured at different H₂ O/1,4-dioxane ratios. Similarly, when increasing the water content, a hypsochromic shift was observed that resulted from H-type aggregation. Furthermore, geometry and electronic configurations of PTZTID were studied at density functional theory /B3LYP level and indicated that the compound had a nonplanar (butterfly structure).

The synthesis and application of (E)-N′-(benzo[d]dioxol-5-ylmethylene)-4-methyl-benzenesulfonohydrazide for the detection of carcinogenic lead

A sensitive cationic sensor was developed by BDMMBSH onto GCE with 5% Nafion using electrochemical method, which was validated with the selective determination of Pb²⁺ in spiked samples and found satisfactory results.

Enzyme-free detection of uric acid using hydrothermally prepared CuO·Fe2O3 nanocrystals

Copper oxide doped iron oxide nanocrystals (CuO·Fe₂O₃ NCs) were prepared using a simple hydrothermal technique at low temperature in an alkaline medium.

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.

Determination of Heavy Metals in Herbal Food Supplements using Bismuth/Multi-walled Carbon Nanotubes/Nafion modified Graphite Electrodes sourced from Waste Batteries

An electrochemical sensor based on graphite electrode extracted from waste zinc-carbon battery is developed. The graphite electrode was modified with bismuth nanoparticles (BiNP), multi-walled carbon nanotubes (MWCNT) and Nafion via the drop coating method. The bare and modified graphite electrodes were used as the working electrode in anodic stripping voltammetry for the determination of trace amounts of cadmium (Cd²⁺) and lead (Pb²⁺). The modified electrode exhibited excellent electroanalytical performance for heavy metal detection in comparison with the bare graphite electrode. The linear concentration range from 5 parts per billion (ppb) to 1000 ppb (R² = 0.996), as well as detection limits of 1.06 ppb for Cd²⁺ and 0.72 ppb for Pb²⁺ were obtained at optimized experimental conditions and parameters. The sensor was successfully utilized for the quantification of Cd²⁺ and Pb²⁺ in herbal food supplement samples with good agreement to the results obtained by atomic absorption spectroscopy. Thus, the BiNP/MWCNT/Nafion modified graphite electrode is a cost-effective and environment-friendly sensor for monitoring heavy metal contamination.

Advances in nanomaterial application in enzyme-based electrochemical biosensors: a review

Electrochemical enzyme-based biosensors are one of the largest and commercially successful groups of biosensors. Integration of nanomaterials in the biosensors results in significant improvement of biosensor sensitivity, limit of detection, stability, response rate and other analytical characteristics. Thus, new functional nanomaterials are key components of numerous biosensors. However, due to the great variety of available nanomaterials, they should be carefully selected according to the desired effects. The present review covers the recent applications of various types of nanomaterials in electrochemical enzyme-based biosensors for the detection of small biomolecules, environmental pollutants, food contaminants, and clinical biomarkers. Benefits and limitations of using nanomaterials for analytical purposes are discussed. Furthermore, we highlight specific properties of different nanomaterials, which are relevant to electrochemical biosensors. The review is structured according to the types of nanomaterials. We describe the application of inorganic nanomaterials, such as gold nanoparticles (AuNPs), platinum nanoparticles (PtNPs), silver nanoparticles (AgNPs), and palladium nanoparticles (PdNPs), zeolites, inorganic quantum dots, and organic nanomaterials, such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), carbon and graphene quantum dots, graphene, fullerenes, and calixarenes. Usage of composite nanomaterials is also presented.

Arsenic sensor development based on modification with (E)-N′-(2-nitrobenzylidine)-benzenesulfonohydrazide: a real sample analysis

(E)-N′-(2-Nitrobenzylidene)-benzenesulfonohydrazide was prepared from 2-nitrobenzaldehyde and benzenesulfonylhydrazine by using a condensation method and applied as a selective As³⁺ sensor.

d-Glucose sensor based on ZnO·V2O5 NRs by an enzyme-free electrochemical approach

A simple wet-chemical technique was used to prepare zinc oxide-doped vanadium pentaoxide nanorods (ZnO·V₂O₅ NRs) in an alkaline environment. The synthesized ZnO·V₂O₅ NRs were characterized using typical methods, including UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (XEDS), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). The d-glucose (d-GLC) sensor was fabricated with modification of a slight coating of nanorods (NRs) onto a flat glassy carbon electrode (GCE). The analytical performances, such as the sensitivity, limit of quantification (LOQ), limit of detection (LOD), linear dynamic range (LDR), and durability, of the proposed d-GLC sensor were acquired by a dependable current–voltage (I–V) process. A calibration curve of the GCE/ZnO·V₂O₅ NRs/Nf sensor was plotted at +1.0 V over a broad range of d-GLC concentrations (100.0 pM–100.0 mM) and found to be linear (R² = 0.6974). The sensitivity (1.27 × 10⁻³ μA μM⁻¹ cm⁻²), LOQ (417.5 mM), and LOD (125 250 μM) were calculated from the calibration curve. The LDR (1.0 μM–1000 μM) was derived from the calibration plot and was also found to be linear (R² = 0.9492). The preparation of ZnO·V₂O₅ NRs by a wet-chemical technique is a good advancement for the expansion of nanomaterial-based sensors to support enzyme-free sensing of biomolecules in healthcare fields. This fabricated GCE/ZnO·V₂O₅ NRs/Nf sensor was used for the recognition of d-glucose in real samples (apple juice, human serum, and urine) and returned satisfactory and rational outcomes.

A simple wet-chemical technique was used to prepare zinc oxide-doped vanadium pentaoxide nanorods (ZnO·V₂O₅ NRs) in an alkaline environment.

Crystal structure and Hirshfeld surface analysis of two (E)-N'-(para-substituted benzyl-idene) 4-chloro-benzene-sulfono-hydrazides

Two (E)-N'-(p-substituted benzyl-idene)-4-chloro-benzene-sulfono-hydrazides, namely, (E)-4-chloro-N'-(4-chloro-benzyl-idene)benzene-sulfono-hydrazide, C13H10Cl2N2O2S, (I), and (E)-4-chloro-N'-(4-nitro-benzyl-idene)benzene-sulfono-hydrazide, C13H10ClN3O4S, (II), have been synthesized, characterized and their crystal structures studied to explore the effect of the nature of substituents on the structural parameters. Compound (II) crystallized with two independent mol-ecules [(IIA) and IIB)] in the asymmetric unit. In both compounds, the configuration around the C=N bond is E. The mol-ecules are twisted at the S atom with C-S-N-N torsion angles of -62.4 (2)° in (I), and -46.8 (2)° and 56.8 (2)° in the mol-ecules A and B of (II). The 4-chloro-phenyl-sulfonyl and 4-substituted benzyl-idene rings form dihedral angles of 81.0 (1)° in (I), 75.9 (1)° in (IIA) and 73.4 (1)° in (IIB). In the crystal of (I), mol-ecules are linked via pairs of N-H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(8) ring motif. The dimers are linked by C-Cl⋯π inter-actions, forming a three-dimensional structure. In the crystal of (II), mol-ecules are linked by C-H⋯π inter-actions and N-H⋯O hydrogen bonds, forming -A-B-A-B- chains along the c-axis direction. The chains are linked via C-H⋯O and C-H⋯π inter-actions, forming layers parallel to the bc plane. Two-dimensional fingerprint plots show that the most significant contacts contributing to the Hirshfeld surface for (I) are H⋯H contacts (26.6%), followed by Cl⋯H/H⋯Cl (21.3%), O⋯H/H⋯O (15.5%) and Cl⋯C/C⋯Cl (10.7%), while for (II) the O⋯H/H⋯O contacts are dominant, with a contribution of 34.8%, followed by H⋯H (15.2%), C⋯H/H⋯C (14.0%) and Cl⋯H/H⋯Cl (10.0%) contacts.

Crystal structures and the Hirshfeld surface analysis of (E)-4-nitro-N'-(o-chloro, o- and p-methyl-benzyl-idene)benzene-sulfono-hydrazides

The crystal structures of (E)-N'-(2-chloro-benzyl-idene)-4-nitro-benzene-sulfono-hydrazide, C13H10ClN3O4S (I), (E)-N'-(2-methyl-benzyl-idene)-4-nitro-benzene-sulfono-hydrazide, C14H13N3O4S (II), and (E)-N'-(4-methyl-benzyl-idene)-4-nitro-benzene-sulfono-hydrazide monohydrate, C14H13N3O4S·H2O (III), have been synthesized, characterized and their crystal structures determined to study the effects of the nature and sites of substitutions on the structural parameters and the hydrogen-bonding inter-actions. All three compounds crystallize in the monoclinic crystal system, with space group P21 for (I) and P21/c for (II) and (III). Compound (III) crystallizes as a monohydrate. All three compounds adopt an E configuration around the C=N bond. The mol-ecules are bent at the S atom with C-S-N-N torsion angles of -59.0 (3), 58.0 (2) and -70.2 (1)° in (I), (II) and (III), respectively. The sulfono-hydrazide parts are also non-linear, as is evident from the S-N-N-C torsional angles of 159.3 (3), -164.2 (1) and 152.3 (1)° in (I), (II) and (III), respectively, while the hydrazide parts are almost planar with the N-N=C-C torsion angles being -179.1 (3)° in (I), 176.7 (2)° in (II) and 175.0 (2)° in (III). The 4-nitro-substituted phenyl-sulfonyl and 2/4-substituted benzyl-idene rings are inclined to each other by 81.1 (1)° in (I), 81.4 (1)° in (II) and 74.4 (1)° in (III). The compounds show differences in hydrogen-bonding inter-actions. In the crystal of (I), mol-ecules are linked via N-H⋯O hydrogen bonds, forming C(4) chains along the a-axis direction that are inter-connected by weak C-H⋯O hydrogen bonds, generating layers parallel to the ac plane. In the crystal of (II), the amino H atom shows bifurcated N-H⋯O(O) hydrogen bonding with both O atoms of the nitro group generating C(9) chains along the b-axis direction. The chains are linked by weak C-H⋯O hydrogen bonds, forming a three-dimensional framework. In the crystal of (III), mol-ecules are linked by Ow-H⋯O, N-H⋯Ow and C-H⋯O hydrogen bonds, forming layers lying parallel to the bc plane. The fingerprint plots generated for the three compounds show that for (I) and (II) the O⋯H/H⋯O contacts make the largest contributions, while for the para-substituted compound (III), H⋯H contacts are the major contributors to the Hirshfeld surfaces.

Anthracene-Based Highly Selective and Sensitive Fluorescent "Turn-on" Chemodosimeter for Hg2

Three π-extended anthracene-bearing thioacetals (1-3) have been synthesized, and their fluorescence "turn-on" responses to Hg2+ ions are studied. The chemodosimetric fluorescence-sensing behavior and their resulting hydrolysis via a desulfurization reaction mechanism leads to the formation of highly fluorescent respective aldehyde substitutions. Furthermore, this mechanism was supported by increase in the quantum yields of their resulting aldehydes and is correlated to their molecular substitution. The chemosensors 1-3 have exhibited to be promising receptors toward Hg2+ ions in the presence of other competitive metal ions. Moreover, the detection limits of 1-3 have been found to be in the nanomolar range (94, 59, and 235, respectively). Fluorescence microscopic imaging studies show that 1-2 have been found to be effective for fluorescence imaging in live cells. Moreover, compounds 1-3 act as potential candidates for the detection of Hg2+ in environmental and biological systems as well as real samples.

Chemical sensing platform for the Zn+2 ions based on poly(o-anisidine-co-methyl anthranilate) copolymer composites and their environmental remediation in real samples

A novel nanostructure of poly(o-anisidine-co-methyl anthranilate) (poly(Ani-Co-MA) copolymer has been synthesized by chemical oxidative in situ polymerization technique with equal molar proportion of monomers in the presence of sodium dodecylbenzene sulfonic acid (SDBS) surfactant. The synthesized copolymers were characterized by scanning electron microscope (SEM) and X-ray crystallography (XRD), Fourier transform infrared (FTIR), UV-Vis, thermo-gravimetric analysis (TGA), and simultaneous X-ray photoelectron spectroscopy (XPS) study. The ultraviolet visible spectrum shows the π to π∗ transition and n to π∗ transition. XRD diffraction pattern confirms the amorphous nature of poly(Ani-Co-MA)-SDBS composites. The scanning electron microscope image shows the morphology of the copolymer matrix. For the selective detection of Zn⁺² cation in neutral phosphate buffer, it was fabricated Zn⁺² cation sensor based on glassy carbon electrode (GCE) coated with poly(Ani-co-MA)-SDBS composites as a thin layer with conducting coating binders. The proposed cation sensor has been found to exhibit the inertness in air and chemical environment, long-term stability with good sensitivity, a broad linear dynamic range practically, a reliable reproducibility, short response time, and high electrochemical activity. The sensitivity (0.3560 μA μM^-1 cm^-2) of Zn⁺² cation sensor has been calculated from the slope of the calibration curve. The linearity of the calibration curve is found over the linear dynamic range (LDR) 0.1 nM~0.01 M, and detection limit (DL) is 27.0 ± 1.35 pM at the signal to noise ratio of 3. This novel effort may be considered quite reliable and effective to detect Zn⁺² cation in environmental and biomedical sectors on a broad scale. Simultaneously, SDBS doped poly(o-anisidine-co-methyl anthranilate) copolymer composites were measured against medically important organisms Escherichia coli. E. ludwigi, and Bacillus subtilis. Graphical abstract ᅟ.

Fabrication of a Ga3+ sensor probe based on methoxybenzylidenebenzenesulfonohydrazide (MBBSH) by an electrochemical approach

A thin-layer of (E)-N′-methoxybenzylidenebenzenesulfonohydrazide (MBBSH) was fabricated by the deposition of MBBSH onto a smooth glassy carbon electrode with nafion binder for the sensitive and selective Ga³⁺ sensor probe.

Fabrication of Sb3+sensor based on 1,1′-(-(naphthalene-2,3-diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen-2-ol)/nafion/glassy carbon electrode assembly by electrochemical approach

A new Schiff base named 1,1′-(-(naphthalene-2,3-diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen-2-ol) (NDNA) was synthesized by condensation reaction and then characterized by spectroscopic techniques for structure elucidation.

A Ce2+ sensor based on napthalen-1-yl-methylene-benzenesulfonohydrazide (NMBSH) molecules: ecological sample analysis

A sensitive and selective Ce²⁺ sensor was developed based on napthalen-1-yl-methylene-benzenesulfonohydrazide (NMBSH) derivatives via an electrochemical approach.

pH-Regulated Synthesis of Trypsin-Templated Copper Nanoclusters with Blue and Yellow Fluorescent Emission

In this article, a simple protocol to prepare water-soluble fluorescent copper nanoclusters (CuNCs) using trypsin as a stabilizer and hydrazine hydrate as a reducing agent was reported. It was found that the pH of the reaction solution was critical in determining the fluorescence of CuNCs. CuNCs with blue and yellow fluorescent emission were obtained under basic and acidic conditions, respectively. Although the detailed formation mechanisms of these CuNCs required further analysis, the synthetic route was promising for preparing different fluorescent metal NCs for applications. With good water solubility and excellent photostability, the yellow-emitting CuNCs could serve as a fluorescence probe for detection of Hg²⁺ based on the aggregation-induced quenching mechanism. The fluorescence quenching efficiency had fantastic linearity to Hg²⁺ concentrations in the range of 0.1-100 μM, with a limit of detection of 30 nM. Additionally, the yellow-emitting CuNCs exhibited negligible cytotoxicity and were successfully applied to bioimaging of HeLa cells.

Trivalent Y3+ ionic sensor development based on (E)-Methyl-N'-nitrobenzylidene-benzenesulfonohydrazide (MNBBSH) derivatives modified with nafion matrix

(E)-Methyl-N'-nitrobenzylidene-benzenesulfonohydrazide (MNBBSH) compounds were synthesized using a condensation procedure from the derivatives of nitrobenzaldehyde and 4-Methyl-benzenesulfonylhydrazine, which crystallized in ethanol and methanol as well as characterized by FTIR, UV-Vis, 1H-NMR, and 13C-NMR. MNBBSH structure was confirmed using a single crystal X-ray diffraction technique and used for the detection of selective yttrium ion (Y3+) by I-V system. A thin layer of MNBBSH was deposited onto a glassy carbon electrode (GCE) with 5% nafion for the sensitive and selective Y3+ sensor. The modified MNBBSH/GCE sensor is exhibited the better electrochemical performances such as sensitivity, limit of detection (LOD), linear dynamic range (LDR), limit of quantification (LOQ), short response time, and long term storage ability towards the selective metal ion (Y3+). The calibration curve of 2-MNBBSH/GCE sensor was plotted at +1.1 V over a broad range of Y3+ concentration. Sensitivity, LOD, LDR and LOQ of the fabricated sensor towards Y3+ were calculated from the calibration curve and found as 1.90 pAμM-1 cm-2, 10.0 pM, 1.0 nM~1.0 mM and 338.33 mM respectively. The 2-MNBBSH/Nafion/GCE sensor was applied to the selective determination of Y3+ in spiked samples such as industrial effluent and real water samples from different sources, and found acceptable and reasonable results.