An environmentally sustainable optode has been developed for the detection of copper ions in water-based solutions. The optode was created by immobilizing 2-[6-nitro-2-benzothiazolylazo]-4-hydroxybenzoic acid (NBTHB) onto a porous cellulosic polymer membrane. This immobilization technique is especially beneficial for dye molecules that tend to degrade in alkaline ethylenediamine solutions, which are frequently employed during optode fabrication. The optode demonstrated a linear response to copper(II) ions within the concentration range of 10 to 130 ng mL–1, achieving a high correlation coefficient of 0.9990. The quantification and detection limits were determined to be 10 and 3.0 ng mL–1, respectively. The precision results were reported as % RSD, with intra-day values of 2.30% and 1.65%, and inter-day values of 2.15% and 1.85%, respectively. The selectivity of the sensor membrane was rigorously tested for a various cations and anions, successfully establishing the tolerance limits for interfering species. It could be effectively regenerated by treatment with 0.1 M EDTA, restoring its functionality for repeated use. The optode was effectively employed to measure copper(II) ions in a range of food products, biological fluids, and environmental water samples. The results obtained were comparable to those achieved using the ICP-AES technique, demonstrating the optodes reliability and accuracy.

Herein, a pioneering methodology for the quantification of minute amounts of silver is introduced, using 2-nitro-6-(thiazol-2-yl-diazenyl)phenol (NTDP) as a complexing agent and Triton X-100 as a nonionic surfactant.

A specialized optical chemical sensor for boron detection was designed using a polymer inclusion membrane (PIM). This unique sensor relies on an encapsulation method to create its optical membrane. The components involved in this sensor include azomethine H (AMH) as the reactive agent, polyvinyl chloride as the foundational polymer, and dinonylnaphthalene sulphonic acid (DNNS) as the extraction agent within the PIM structure. Various parameters, such as membrane thickness, concentration of AMH and DNNS, plasticizer proportions, stirring dynamics, and the pH of the solution under study, significantly affected the sensor’s performance. Within a detection range spanning 4.0–116 ng mL−1 of boron, the sensor demonstrated a strong linear relationship with detection and quantification thresholds of 1.25 and 3.94 ng mL−1, respectively. The peak absorption wavelength (λmax) for this PIM-based sensor was identified at 424 nm. Moreover, the sensor displayed a reproducibility (RSD) of 1.65

A novel, precise, and targeted method has been developed for isolating, preconcentrating, and analyzing gold ions in water, ore, and food samples.

An optode featuring high selectivity was prepared for cadmium detection via chemically binding β-2-hydroxybenzyl-5-chloro-2-hydroxyazastyrene (HCHAS) onto a clear agarose membrane. Colorimetric analysis of complexation between HCHAS and various metal ions at pH 2.75 revealed that the Cd2+ complex exhibited a markedly higher stability constant than others. As a result, HCHAS was applied as a suitable ionophore for fabricating a Cd2+-selective optode, via chemically anchoring it onto a transparent agarose matrix. The immobilization parameters were optimized and the resulting optode represented a conspicuous color transition from yellow to purple as a result of increasing Cd2+ concentrations in a pH 2.75 buffered solution. Detailed investigations were conducted to assess the influence of pH, ionophore loading, ionic strength, stirring conditions, and reaction duration on the optode's performance. A strong linear relationship was observed over the 4.0-140 ng mL-1 concentration range, with R2 values of 0.9882 and 0.9990, respectively. The high sensitivity of the method was demonstrated by the molar absorptivity and Sandell sensitivity, evaluated at 5.11 × 106 L mol-1 cm-1 and 0.002 ng cm-2, respectively. Furthermore, Cd2+ detection was not considerably influenced by the existence of various potentially interfering ions at concentrations 500-fold higher. The fabricated optode was effectively utilized for the quantification of cadmium ions in fortified food, environmental and biological specimens.

Regulating interfacial kinetics at the Mg metal anode is crucial to advancing the performance of magnesium-sulfur (Mg-S) batteries. In this study, we present a novel strategy by introducing thiourea (TU) additives to a halogen-free electrolyte (HFE), aiming to stabilize the Mg-electrolyte interface and enhance Mg2+ transport. The optimized TU content (0.05-0.2 g) added to 1.5 g of Mg(NO3)2·6H2O improves ion mobility, increases the transference number to 0.81, and enhances ionic conductivity. Coin cells assembled with TU-modified electrolytes exhibit an initial discharge capacity of 880 mAh g-1 and more stable electrochemical behavior over the early cycles, along with reduced polysulfide diffusion compared to that of the pristine system. Comprehensive characterizations (X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS)) confirm that the TU additive facilitates the formation of a more uniform and stable interfacial layer on the Mg anode surface. These findings demonstrate that interfacial kinetics can be effectively regulated through simple electrolyte engineering, offering a promising route to enhance the electrochemical performance of Mg-S batteries.

A new selective optode has been created for the ultra-sensitive detection of lead ions at trace levels. The membrane is created by incorporating tri-n-octylphosphine oxide (TOPO), 2-amino-4-(4-nitrophenyl)diazenyl pyridine-3-ol (ANPDP), and sodium tetraphenylborate (Na-TPB) into a matrix of plasticized poly(vinyl chloride) (PVC) and o-nitrophenyloctyl ether (o-NPOE). ANPDP serves as a chromophore in this design, while TOPO promotes the formation of a complex between lead ions (Pb2+) and ANPDP, resulting in a cooperative interaction. The composition of the optode was optimized to achieve maximum sensor performance. The sensor exhibits a linear dynamic range from 6.0 to 160 ng mL-1, with quantification and detection limits of 5.9 ng mL-1 and 1.8 ng mL-1, respectively. The membrane demonstrated rapid response times and long-term durability, with no detectable leaching of ANPDP. To ensure accurate total lead determination, Pb4+ ions were reduced to Pb2+ using 6.00 M HCl and freshly prepared 2.50% (w/v) sodium azide. The optode sensor exhibited superior specificity for Pb2+ ions, even when other ions that could potentially interfere were present. It could be effectively regenerated by treatment with 0.1 M ethylenedi-aminetetraacetic acid (EDTA), restoring its functionality for repeated use. The sensor was successfully applied to detect lead in various complex matrices, including biological fluids, environmental water, and food samples, demonstrating its broad applicability and reliability for real-world lead monitoring.

The new reagent 6-{4-(2,4-dihydroxyphenyl)diazenyl)phenyl}-2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile (DDPODC), was checked for its possible application in a lanthanum-selective optical sensor membrane. The DDPODC was fixed onto a triacetylcellulose membrane. When lanthanum ions are present in an acetate buffer at pH 4.53, the membrane's color transforms from orange to violet. The sensor's response time was within 5.0 min, influenced by the amount of La(III) ions. The effects of pH, DDPODC quantity, and timing of reaction were examined. At a wavelength of 598 nm, the membrane revealed a linearity range of 5.0-180 ng mL-1 with a limit of detection of 1.35 ng mL-1 under optimal experimental circumstances. The Sandell sensitivity was evaluated at 0.0183 ng cm-2, and the molar absorptivity was estimated to be 7.58 x 105 L mol-1 cm-1. The suggested sensor demonstrated remarkable selectivity for lanthanides, actinides, and transition metal ions, as well as a low limit of detection with a rapid reaction time. With a relative standard deviation (RSD) of less than 1.15%, the optical sensor demonstrated a potentially reversible and reproducible response after being successfully regenerated utilizing a thiourea solution. La3+ ions in environmental samples were successfully detected by the sensor.

A sustainable method is investigated for the accurate, selective, and highly sensitive identification of minimal nickel ion concentrations across various environments. A unique optical sensing membrane is proposed for detecting Ni2+ ions, utilizing the entrapment of 5-(2-benzothiazolylazo)-8-hydroxy-quinoline (BTAHQ) within a matrix of polyvinyl chloride (PVC) combined with dioctyl adipate (DOA). The sensor exhibits a broad linear span ranging from 2.5 to 110 ng mL- 1 under pH 4.0 conditions, featuring quantification and detection limits of 2.47 and 0.75 ng mL- 1, respectively. The sensor's maximum wavelength is recorded at 659 nm. Remarkably, the sensor membrane exhibits complete reversibility in its operation, showcasing superior specificity for Ni2+ ions even in the presence of a wide range of competing cations and anions within the solution. The membrane exhibited excellent durability for 3.0 min, featured a swift response time (5.0 min), and demonstrated no detectable signs of reagent leaching. The sensor response exhibited a low coefficient of variation (CV) of 1.47 % for 60 ng mL- 1 of Ni2+ ions, and the CV among seven sensor membranes was 1.63 %. Regenerating the sensor is a straightforward process accomplished with 0.5 mL of 0.1 M HNO3 solution for 3.0 min. Its full reversibility and excellent selectivity for Ni2+ ions in thiel buffer contribute to its efficacy. The suggested optical sensor was effectively employed for nickel determination in food and water samples.

Schematic representation for the preparation and complexation of Zr( iv ) ions on the formed optical sensor.

A re-generable optical chemical sensing film was created using a modified chitosan film that incorporates immobilized 4-(thiazol-2-yldiazenyl) benzene-1,3-diol (TDBD) for the detection of Co2+ in acidic aqueous solutions. Upon exposure to Co2+, the film's color shifted from yellowish green to red by forming a complex between Co2+ and TDBD. The sensor's complex was measured at 574 nm, a wavelength where the sensing membrane exhibited minimal background interference. The film exhibited its highest responsiveness to cobalt ions at pH 5.0. Two sample volumes were analysed: 2.5 mL with a Co2+ concentration range of 8.0-140 ng/mL, and 250 mL with a concentration range of 2.4-15.2 ng/mL. Both sample sizes produced linear calibration curves, with detection limits of 2.5 and 0.7 ng/mL, respectively. The relative standard deviation was 1.35 % for six separate films in a 100 ng/mL Co2+ solution, and 0.87 % for six individual films in a 10 ng/mL solution using 2.5 and 250 ng/mL, respectively. The sensing films demonstrated good stability over 30 days and were successfully used to determine Co2+ in pharmaceutical, food, environmental, and biological samples, yielding satisfactory results compared to the ICP-AES method.

Voriconazole, a pivotal antifungal agent, has been analysed using two uncomplicated, sensitive, rapid, and validated spectrophotometric methods. These procedures rely on the formation of charge transfer complexes in methanol, employing alizarin red S and quinalizarin as chromogenic reagents, each exhibiting absorption maxima at 568 and 513 nm, respectively. The optimisation of reaction conditions was explored, encompassing the choice of solvent, reagent concentration, and reaction duration. Both alizarin red S and quinalizarin demonstrated excellent adherence to Beer's law over concentration ranges of 1.0-18 and 1.0-24 mu g mL(-1), respectively, with robust correlation coefficients (r(2) >= 0.9993) and minimal relative standard deviations (RSD% <= 1.04). Additionally, calculations were conducted for molar absorptivity (1.1256x104 and 1.7624 x104 L mol(-1) cm(-1)), Sandell sensitivity (31.0 and 19.82 ng cm(-2)), detection and quantification limits (0.3 and 1.0 mu g mL(-1)) for alizarin red S and quinalizarin, respectively. Both methods were effectively applied for the determination of voriconazole in dosage forms, and their validity was confirmed using the standard addition technique. The results obtained from these proposed procedures for pure and dosage forms closely matched those from previously reported methods.

A novel optical probe has been successfully developed for the selective detection of Os(VIII) ions. This osmium-sensing platform was intricately designed by incorporating 4-(thiazol-2-yldiazenyl)benzene-1,3-diol (TDBD) as the ionophore within a plasticized PVC membrane, and tributylphosphate (TBP) serving as the plasticizer. Upon exposure to Os(VIII) ions in a 0.5 M HClO4 acid milieu, the sensing membrane undergoes a distinctive chromatic transition, shifting from a yellow to a pink hue. The preparation of the sensor and the methodology for Os(VIII) determination were meticulously refined to achieve optimal performance. Under these carefully optimized experimental conditions, the proposed optode demonstrated an impressive linear detection range spanning from 2.5 × 10−9 to 2.5 × 10−5 M for Os(VIII), alongside remarkable detection and quantification limits of 7.24 × 10−10 and 2.4 × 10−9 M, respectively. The sensor consistently delivered highly reproducible results, as evidenced by relative standard deviation (RSD) values of 1.45% and 1.30% for Os(VIII) concentrations at 7.5 × 10−7 and 2.5 × 10−6 M, respectively, underscoring its precision and reliability. Furthermore, the sensor exhibited a swift response time of 3.0 min, further emphasizing its efficiency. The incorporation of PIMs into the sensor architecture led to a remarkable eight-fold enhancement in its response compared to counterparts lacking PIMs, signifying a significant performance improvement. In assessing potential interference, an investigation into the influence of other ions on Os(III) determination revealed that the prepared sensor displayed exceptional selectivity for Os(VIII) ions, with negligible responses observed in the presence of common ions. Collectively, these experimental findings underscore the sensor's efficacy as an invaluable tool for the precise analysis of osmium content in water samples, aligning it with the rigorous standards of international scientific research.

We herein report a direct and facile hydrothermal method for the preparation of zero-valent silver nanoparticles using a mixture of ascorbic acid/starch as a reducing agent. The average crystallite size of the prepared Ag0 nanoparticles was ca. 46.7 nm. The zero-valent silver nano-products were characterized by using FT-IR, FE-SEM, and XRD analyses. In addition, this work shows an improved synthesis of graphene oxide nanoparticles. The average crystallite size of the prepared graphene-oxide nanoparticles was ca. 6.0nm. The graphene oxide nanoparticles were also characterized by using FT-IR, FE-SEM, and XRD analyses.

Beryllium (Be2+) is a type of alkaline earth-divalent metal that enters many strategic industries. The work environment limits concentrations of beryllium is in the range of 0.01 - 1.0 mu g mL-1 (ppm), where concentrations exceeding 5.0 ppm of Be2+ lead to acute toxicity, causing pulmonary edema and chemical pneumonitis. Herein, Be2+ was measured selectively in situ down to ultralow concentration levels utilizing a fabricated sensitive polymer inclusion membrane (PIM) as an immobilizing non-plasticized colorimetric optical sensor (optode). The PIM-sensitive optode has been created using an encapsulation method with polyvinyl chloride (PVC) as a polymer base, an (E)-6-(4-((2,5-dihydroxyphenyl)diazenyl)phenyl)-2-oxo-4-phenyl-1,2-dihydropyridine-3-carbonitrile (DDP-OPDC) as a selective ligand, and Aliquat 336 as an enhancer extractant. The linear dynamic range of the various standard measurements ranged between 5.0 and 145 ng mL-1 with excellent sensitivity down to 1.6 ng mL-1. Moreover, the manufactured optode was reusable and had sustainable mechanical strength. The method has also successfully quantified Be2+ in the livers and muscles of bovine, chicken, and pork (recovery %; 98.0---102.3 %) in addition to Be2+ analysis in contaminated tap, mineral, and well water (recovery %; in the range of 93.6---103.3 %). With an assessment duration of 10 min at a maximum absorbance of 622 nm, the colorimetric evaluations of Be2+ in various samples (water and biological) were rapid, reliable, and reproducible. Furthermore, the obtained results by the developed optode matched excellently those obtained by the comparison atomic absorption spectrometry method.

The development of a highly selective and ultra-sensitive optical sensor for detecting scandium (Sc3+) ions involves incorporating the reagent 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) into a silica sol–gel thin film on a glass substrate. This innovative approach utilizes tetraethoxy-silane (TEOS) as the precursor, maintaining a sol–gel pH level of 4.5, a water-to-alkoxide ratio of 5:1, and a DCHNAQ concentration of 5.0 × 10−4 M. A detailed exploration of the impact of sol–gel parameters on the sensing capabilities of the developed sensor has been meticulously undertaken. This innovative sensor demonstrates remarkable selectivity in evaluating Sc3+ ions over a dynamic range of 7.5–170 ng/mL, with limits of quantification and detection recorded at 7.3 and 2.20 ng/mL, respectively. Consistent results are achieved with a minimal RSD of 1.47 and 0.94

A novel sensitive, specific, and reversible optical sensor for the palladium( ii ) ion was created by impregnating an agarose membrane with 4-(2-amino-3-hydroxypyridine-4-ylazo)1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one (AHDDO).