scholarly journals Paper-Based Device for Sweat Chloride Testing Based on the Photochemical Response of Silver Halide Nanocrystals

Chemosensors ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 286
Author(s):  
Tatiana G. Choleva ◽  
Christina Matiaki ◽  
Afroditi Sfakianaki ◽  
Athanasios G. Vlessidis ◽  
Dimosthenis L. Giokas
Keyword(s):  
Color Change ◽  
Silver Chloride ◽  
Uv Light ◽  
Silver Halide ◽  
Chloride Concentration ◽  
Silver Ions ◽  
Absolute Difference ◽  
Color Intensity ◽  
Paper Surface

A new method for the determination of chloride anions in sweat is described. The novelty of the method relies on the different photochemical response of silver ions and silver chloride crystals when exposed to UV light. Silver ions undergo an intense colorimetric transition from colorless to dark grey-brown due to the formation of nanosized Ag while AgCl exhibits a less intense color change from white to slightly grey. The analytical signal is obtained as mean grey value of color intensity on the paper surface and is expressed as the absolute difference between the signal of the blank (i.e., in absence of chloride) and the sample (i.e., in the presence of chloride). The method is simple to perform (addition of sample, incubation in the absence of light, irradiation, and offline measurement in a flatbed scanner), does not require any special signal processing steps (the color intensity is directly measured from a constant window on the paper surface without any imager processing) and is performed with minimum sample volume (2 μL). The method operates within a large chloride concentration range (10–140 mM) with good detection limits (2.7 mM chloride), satisfactory recoveries (95.2–108.7%), and reproducibility (<9%). Based on these data the method could serve as a potential tool for the diagnosis of cystic fibrosis through the determination of chloride in human sweat.

scholarly journals Characterization and Applications of Silver Sulphide Based Membrane Electrodes

1970 ◽  
Vol 7 (7) ◽  
pp. 19-23 ◽  
Author(s):  
A Rajbhandari ◽  
AP Yadav ◽  
K Manandhar ◽  
RR Pradhananga
Keyword(s):  
Silver Chloride ◽  
Silver Halide ◽  
Ion Selective Electrode ◽  
Ion Selective Electrodes ◽  
Powder Materials ◽  
Membrane Electrodes ◽  
Selective Electrode ◽  
Sulphide Ions ◽  
Silver Sulphide

The polycrystalline materials obtained by co-precipitation of silver sulphide and appropriate silver halide are used to prepare silver sulphide based membrane electrodes selective to the silver, chloride, bromide, iodide, and sulphide ions. The powder materials are characterized by x-ray diffraction, SEM equipped with EDAX. These membrane electrodes are found to give Nernstian response with the appropriate ions in the concentration range from 1x10-1 to 1x10-5 M. The performance of these home made electrodes is at par with the commercial electrodes. The electrodes have been successfully used for the quantitative determination of chloride, bromide iodide, silver, and sulphide ions and also for the determination of thiamine in pharmaceutical preparations. For developing countries like Nepal, who can not afford to procure high cost commercial ion selective electrodes, these home made ion selective electrodes are especially appealing since the electrode can be fabricated with ease in low cost and the electrode is well behaved and sufficiently accurate for the analysis with ion selective electrodes. Key words: Ion selective electrode; Home made ion selective electrode; Silver sulphide; Thiamine; Vitamin B1. DOI: 10.3126/sw.v7i7.3818 Scientific World Vol.7(7) 2009 pp.19-23  

scholarly journals Benzimidazole-functionalized fluorescent probe for rapid detection of 2,4,6-trinitrophenol and Ag+ in semiaqueous medium

2021 ◽  
pp. 9-9
Author(s):  
Bin Wang ◽  
Fan Jiang ◽  
Xixi Zuo ◽  
Jing Ma ◽  
Xiangmei Ma
Keyword(s):  
Fluorescence Quenching ◽  
Color Change ◽  
Uv Light ◽  
Potential Candidate ◽  
Quenching Mechanism ◽  
Naked Eye ◽  
Uv Light Irradiation ◽  
Fluorescence Quenching Mechanism ◽  
Selective Sensor

In this study, a simple fluorescent chemosensor with good fluorescence properties was synthesized, which was used to develop a sensitive and selective sensor for the determination of 2,4,6-trinitrophenol (TNP) and Ag+ in THF/H2O medium based on the fluorescence quenching mechanism. Fluorescence quenching experiments revealed that the fluorescence intensities of the resulted probe were linear with the concentrations of TNP and Ag+ in the concentration range of (30-50)?10-7 and (20-50)?10-7 mol dm-3, with the detection limit of 1.36 and 0.82 ?mol dm-3, respectively. At the same time, accompanied with fluorescent color change under 365 nm UV light irradiation. This has demonstrated that the compound can act as a potential candidate for a ?naked-eye? rapidly detector for Ag+ and TNP in soils and aquatic systems.

Oxonol dyes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Heinz Mustroph
Keyword(s):  
Silver Halide ◽  
Medical Diagnostics ◽  
Water Soluble ◽  
Eukaryotic Cells ◽  
Polymethine Dyes ◽  
Technical Application ◽  
Structural Types ◽  
Oxonol Dyes ◽  
Oxygen Atoms

Abstract Oxonol dyes are classified as anionic polymethine dyes, which cover a wide variety of structural types. The name of the class originates from the oxygen atoms which terminate each end of the polymethine chains that form the backbone of their structure. In technically useful dyes, these oxygen atoms tend to be substituents of heterocycles. The main technical application of water soluble oxonol dyes was in silver halide photography as filter dyes and antihalation dyes. Lipophilic oxonol dyes are used in bio-analysis and medical diagnostics to stain cells, bacteria or liposomes for example. Their main bioanalytical usage is in the determination of membrane potentials in eukaryotic cells and prokaryotic bacteria.

scholarly journals Deposition of Zinc Oxide Coatings on Wood Surfaces Using the Solution Precursor Plasma Spraying Process

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 183
Author(s):  
Ghiath Jnido ◽  
Gisela Ohms ◽  
Wolfgang Viöl
Keyword(s):  
Zinc Oxide ◽  
Ftir Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Color Change ◽  
Uv Light ◽  
Beech Wood ◽  
Nitrate Solution ◽  
Ftir Spectra ◽  
Solution Precursor ◽  
Wood Surfaces

In the present work, the solution precursor plasma spray (SPPS) process was used to deposit zinc oxide (ZnO) coatings on wood surfaces using zinc nitrate solution as precursor to improve the hydrophobicity and the color stability of European beech wood under exposure to ultraviolet (UV) light. The surface morphology and topography of the wood samples and the coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The formation of ZnO was detected with the help of X-ray photoelectron spectroscopy (XPS) and by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectra of the coated samples showed the typical Zn–O band at 445 cm−1. According to the XPS analysis, the coatings consist of two different Zn-containing species: ZnO and Zn(OH)2. Variation of the deposition parameters showed that the most significant parameters affecting the microstructure of the coating were the solution concentration, the deposition scan speed, and carrier gas flow rate. The wettability behaviors of the coated wood were evaluated by measuring the water contact angle (WCA). The coatings that completely covered the wood substrates showed hydrophobic behaviors. UV-protection of wood surfaces after an artificial UV light irradiation was evaluated by color measurements and FTIR spectroscopy. The ZnO-coated wood surfaces were more resistant to color change during UV radiation exposure. The total color change decreased up to 60%. Additionally, the FTIR spectra showed that the wood surfaces coated with ZnO had more stability. The carbonyl groups formation and C=C-bonds consumption were significantly lower.

Multi-Array Wax Paper-Based Platform for the Pre-Concentration and Determination of Silver Ions in Drinking Water

Talanta ◽  
2021 ◽  
pp. 122474
Author(s):  
Neda Bagheri ◽  
Stefano Cinti ◽  
Eleonora Nobile ◽  
Danila Moscone ◽  
Fabiana Arduini
Keyword(s):  
Drinking Water ◽  
Silver Ions

scholarly journals Flexible Potentiometric Sensor System for Non-Invasive Determination of Antioxidant Activity of Human Skin: Application for Evaluating the Effectiveness of Phytocosmetic Products

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 76
Author(s):  
Aleksey V. Tarasov ◽  
Ekaterina I. Khamzina ◽  
Maria A. Bukharinova ◽  
Natalia Yu. Stozhko
Keyword(s):  
Antioxidant Activity ◽  
Human Skin ◽  
Skin Diseases ◽  
Silver Chloride ◽  
Potentiometric Sensor ◽  
Sensor System ◽  
Non Invasive ◽  
Pet Film ◽  
The Impact

In contemporary bioanalysis, monitoring the antioxidant activity (AOA) of the human skin is used to assess stresses, nutrition, cosmetics, and certain skin diseases. Non-invasive methods for skin AOA monitoring have certain advantages over invasive methods, namely cost-effectiveness, lower labor intensity, reduced risk of infection, and obtaining results in the real-time mode. This study presents a new flexible potentiometric sensor system (FPSS) for non-invasive determination of the human skin AOA, which is based on flexible film electrodes (FFEs) and membrane containing a mediator ([Fe(CN)6]3–/4–). Low-cost available materials and scalable technologies were used for FFEs manufacturing. The indicator FFE was fabricated based on polyethylene terephthalate (PET) film and carbon veil (CV) by single-sided hot lamination. The reference FFE was fabricated based on PET film and silver paint by using screen printing, which was followed by the electrodeposition of precipitate containing a mixture of silver chloride and silver ferricyanide (SCSF). The three-electrode configuration of the FPSS, including two indicator FFEs (CV/PET) and one reference FFE (SCSF/Ag/PET), has been successfully used for measuring the skin AOA and evaluating the impact of phytocosmetic products. FPSS provides reproducible (RSD ≤ 7%) and accurate (recovery of antioxidants is almost 100%) results, which allows forecasting its broad applicability in human skin AOA monitoring as well as for evaluating the effectiveness of topically and orally applied antioxidants.

A colorimetric sensor for detecting thiourea based on inhibiting peroxidase-like activity of gold–platinum nanoparticles

2021 ◽  
Author(s):  
Yuqi Zhao ◽  
Qingjie Fu ◽  
Xiaoqian Cui ◽  
Hui Chi ◽  
Yongzhuang Lu ◽  
...  
Keyword(s):  
Platinum Nanoparticles ◽  
Color Change ◽  
Colorimetric Sensor ◽  
Gold Platinum

The sensor is based on the peroxidase-like activity of Au@PtNPs. Thiourea can quickly be detected by the color change of the solution. The method was applied to the determination of thiourea in practical samples.

scholarly journals III. On the atomic weight of manganese

1883 ◽  
Vol 35 (224-226) ◽  
pp. 44-48
Keyword(s):  
Carbon Dioxide ◽  
Silver Chloride ◽  
Atomic Weight ◽  
Special Method ◽  
Its Analysis ◽  
A Current ◽  
Sulphuretted Hydrogen

Our attention has been directed for some time to a new determination of the atomic weight of manganese. This communication gives a succinct account of the results of the preliminary stages of such an inquiry, and although the further progress of the investigation may reveal some errors, still we feel convinced the final numbers can in no way differ materially from the present values, and therefore further delay in publication is unnecessary. The atomic weight of manganese has been determined by many chemists, but the resulting values vary considerably according to the special method selected. The results of the different investigators may be divided into two classes—those giving approximately 55 as the number, and those making it about 54. To the former class belong Turner, Berzelius, and Dumas, all of whom use the same method, viz., the determination of the silver chloride yielded by a weighed amount of chloride of manganese. Turner also made determinations from the analysis of the carbonate, and from the conversion of the monoxide into sulphate. Von Hauer used the same method as that employed by him in the determination of the atomic weight of cadmium, viz., the reduction of manganous sulphate to sulphide by ignition in a current of sulphuretted hydrogen. It is probable that this method is not very trustworthy, as, according to Schneider, the sulphide may be contaminated by oxysulphide. Schneider and Rawack belong to the second class of observers, the former employing the oxalate, and from its analysis calculating the atomic weight by deducting the weight of water and carbon dioxide obtained. Rawack, whose experiments were conducted in Schneider’s laboratory, weighed the water obtained by reducing manganoso-manganic oxide to manganous oxide.

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