Trace Amounts Of Chlorine Research Articles

Control of Biological Surface States on Chlorine-Doped Amorphous Silica Particles and Their Effective Absorptive Ability for Antibody Protein.

Amorphous silica particles (ASPs) have low biotoxicity and are used in foodstuffs; however, the adsorption states of proteins on their surfaces have not yet been clarified. If the adsorption states can be clarified and controlled, then a wide range of biological and medical applications can be expected. The conventional amorphous silica particles have the problem of protein adsorption due to the strong interaction with their dense silanol groups and denaturation. In this study, the surfaces of amorphous silica particles with a lower silanol group density were modified with a small amount of chlorine during the synthesis process to form a specific surface layer by adsorbing water molecules and ions in the biological fluid, thereby controlling the protein adsorption state. Specifically, the hydration state on the surface of the amorphous silica particles containing trace amounts of chlorine was evaluated, and the surface layer (especially the hydration state) for the adsorption of antibody proteins while maintaining their steric structures was evaluated and discussed. The results showed that the inclusion of trace amounts of chlorine increased the silanol groups and Si-Cl bonds in the topmost surface layer of the particles, thereby inducing the adsorption of ions and water molecules in the biological fluid. Then, it was found that a novel surface layer was formed by the effective adsorption of Na and phosphate ions, which would change the proportion of the components in the hydration layer. In particular, the proportion of the free water component increased by 21% with the doping of chlorine. Antibody proteins were effectively adsorbed on the particles doped with trace amounts of chlorine, and their steric adsorption states were evaluated. It was found that the proteins were clearly adsorbed and maintained the steric state of their secondary structure. In the immunoreactivity tests using streptavidin and biotin, biotin bound to the chlorine-doped particles showed efficient reactivity. In conclusion, this study is the first to discover the surface layer of the amorphous silica particles to maintain the steric structures of adsorbed proteins, which is expected to be used as a carrier particle for antibody test kits and immunochromatography.

Photocatalytically Generated Pt/C-TiO2 Composite As ORR Catalyst

Metal decorated carbon materials have grabbed the attention of the world due to its tremendous application in various paths of life. Among the various metals decorated over carbon, transition metals like Pt is more talked about when it comes to catalytic reactions in energy devices. Very recently we reported exfoliated acetylene black/Pt nano-particles showing extraordinarily high ORR activity [1]. However, the general methods used for decoration of metal nanoparticles on to carbon substrates are basically carried out by employing sacrificial reducing agents (SRA) like alcohols or other reducing agents at elevated temperatures, which are against to the green approach. Lookout for alternative green procedures has recently ended up in looking into exploiting photo-reduction processes. However, research dealing with the photo-reduction of metal salts to metals in aqueous medium without a SRA is not fully studied [2]. Alongside ‘green’ aspect, large scale commercial applications are precluded by the high manufacturing cost of the ORR catalyst. Hence, researcher have been focusing on reducing the cost of the catalyst by decreasing the amount of Pt used with the introduction of transition metal oxides and doping of nitrogen in carbon. The present work deals with the photo-reduction of chloroplatinic acid on to graphite and graphene using TiO2as photo-catalyst irradiated by solar simulator. Graphite (carbon substrate) weighing 90mg was ultrasonicated in water for 2 hrs to obtain a uniform dispersion. To this uniform dispersion, 10 mg of TiO2and 800 μL of 0.045 M chloroplatinic acid solution was added and ultrasonicated for 15 min. The solution was irradiated using solar simulator for 5 hrs. The reaction completion time was confirmed by studying the open-circuit potential of the solution across Pt wire working electrode and Ag/AgCl reference electrode. The material was then subjected to morphological characterization by TEM and elemental analysis by XPS. Further, the material was studied for its ORR behavior using cyclic voltammetry. TEM micrographs showed uniform distribution of Pt-nps all over the graphite along with TiO2. Platinum nano particles were in the range of 5 to 10 nm in size Fig1 (A and B). Elemental characterization by XPS (Fig 1C) revealed the presence of Pt, O, Ti and C along with trace amounts of chlorine given in Fig. 1D. The reaction completion time was studied using change in the open circuit potential (OCP), which was found to be nearly 4 hrs (Fig. 1E). Oxygen reduction characteristics of the electrocatalyst was studied using cyclic voltammetry. The voltammograms (Fig 1F) confirmed that the prepared material to be a promising catalytic material. The electrochemical active surface area (ECSA) was calculated as 62.24 m2/gm. The ECSA was observed to be significantly high compared to commercial Pt/C catalyst. In conclusion, a highly reproducible, environmentally benign and ultrafast method was developed for the preparation of active ORR catalyst (for use in Fuel cell and Lithium-air battery). The method uses solar light as the only source of energy in the preparation of this catalytically efficient composite utilizing abundant and environmentally benign TiO2 as photo-catalyst. Using this green methodology, preparation of novel composites containing TiO2 particles, graphite substrates and platinum nanoparticles was successfully carried out. As prepared material showed excellent ORR activity comparable to the best of commercial ORR catalysts. It can also be confirmed that this method is feasible for all the conducting carbon substrates. The above results clearly demonstrates that the novel, green and a very viable method of Pt decoration method is as efficient as rather more efficient as that of well-established methods using SRA. References 1) R. Badam, R. Vedarajan, N. Matsumi, Chem. Commun., 2015, 51, 9841. 2) F. Mahlamvana, R.J. Kriek, Appl. Cat. B, 2014, 148-149, 387. Figure 1

Electrodeposition of purified aluminum coatings from dimethylsulfone–AlCl3 electrolytes with trimethylamine hydrochloride

Aluminum (Al) coatings have been electrodeposited from dimethylsulfone (DMSO2)–AlCl3 electrolytes, but the coatings usually contained trace amounts of chlorine (Cl) and sulfur (S) as impurities. Since these impurities make the coatings hard and brittle, and moreover may adversely affect the corrosion- and oxidation-resistances of the Al coatings, it would be desirable to decrease their contents in the Al coatings. Examination of the Al coatings electrodeposited from the electrolytes with the addition of various amounts of trimethylamine hydrochloride (TMA) revealed that the Cl and S contents of the Al coatings decreased with increasing concentration of TMA in the electrolyte. The addition of TMA also brought about changes in the surface morphology and crystal orientation of the Al coatings. Preferential adsorption of TMA on the surface of the Al deposit was inferred to be a cause of the exclusion of Cl and S from the Al coating. As a result of the decrease in Cl and S contents, the Al coatings were softened.

Polymer residue chemical composition analysis and its effect on via contact resistance in dual damascene copper interconnects process integration

During via and trench plasma etching in dual damascene copper interconnects process integration, polymer residues and copper damage were created as by-products of the dry-etch process. The polymer residue chemical composition and copper damage were analyzed by Auger electron spectroscopy. Analysis result indicated that besides copper, carbon, oxygen, and nitrogen and trace amounts of chlorine and sulphur were also observed. The polymer residue and copper damage are the important reasons of cause higher via contact resistance and lower via yield. It could be reduced and eliminated effectively using optimized plasma etch recipe, improved polymer residue removal methods and improved pre-treatment before metal deposition and so on.

Gas-phase composition measurements during chlorine assisted chemical vapor deposition of diamond: A molecular beam mass spectrometric study

We have constructed a molecular beam mass spectrometer designed specifically to sample gases from a diamond chemical vapor deposition (CVD) process chamber thereby enabling characterization of the gas-phase CVD environment. With this in situ diagnostic technique we have obtained quantitative measurements of the composition of the gas-phase species as a function of filament temperature for a variety of C/H/Cl gas mixtures. The precursor mixtures used were 1% of a chloromethane (CH4−nCln, n=1-4) in hydrogen and 1% CH4 in hydrogen with added Cl2 varying from 1% to 4%. At filament temperatures optimum for diamond growth (∼2300°C) the relative CH4/C2H2/C2H4 product distribution measured in the gas mixture is remarkably similar to that established when CH4 is the carbon precursor species. At these filament temperatures almost all the chlorine is reduced to HCl, its concentration being proportional to the Cl fraction in the source gas, regardless of the form of the chlorine in the source gas mixture. Compositional analysis of the as-grown diamond films indicated that no chlorine was present in the bulk of the films, though trace amounts of chlorine were detected on the film surface. From these observations we surmise that chlorine atoms are involved in the gas-surface reactions which produce active growth sites on the diamond surface.

Gas-phase concentration measurements and diamond film composition from chlorine assisted CVD

Molecular beam mass spectrometry has been used to obtain quantitative measurements of the composition of the gas-phase species prevailing during diamond chemical vapour deposition (CVD) using a variety of chlorine containing source gases. Gas mixtures used were 1% of a chlorinated methane (CH4 −n,Cln,n = 1 − 4) in H2 and 1% CH4 in H2 with added chlorine varying from 1%–4%. At filament temperatures optimum for diamond growth (≈2300 °C) the relative concentrations of the various hydrocarbon species (CH4, C2H2, C2H4) in the gas mixture are remarkably similar to those measured when the carbon precursor species is CH4. At these filament temperatures almost all the chlorine is reduced to HCl, its concentration being proportional to the chlorine fraction in the source gas, regardless of the form of the chlorine in the input mixture. Auger electron spectroscopy analysis of the as-grown diamond films indicated that no chlorine was present in the bulk of the films, though trace amounts of chlorine were detected on the film surface. These observations are consistent with the supposition that chlorine atoms are involved in the gas-surface reactions which produce active growth sites on the diamond surface.

Residual contamination and corrosion on electrochemically marked uranium

Residual contamination and potential corrosion problems on uranium parts electrochemically marked with PHB-1 and PHB-1E electroetchants have been investigated using ion microprobe mass analysis (IMMA), scanning electron microscopy (SEM), and light microscopy (LM). The effectiveness of various solvent-cleaning sequences and the influence of the use of an abrasive cleaner were evaluated. The corrosion depths and chlorine distributions resulting from the electroetching process were determined. To meet the objective, the surfaces of uranium coupons, which had been processed according to production procedures for parts, i.e., machining, cleaning, marking, inspecting and coating with Shell Vitrea-29® oil, were studied. The greater surface wetting capability of the PHB-1E electroetchant solution relative to PHB-1 resulted in less localized corrosion at the point of attack which provided a more legible mark. Components of the electroetchants (aluminum, potassium and chromium) were found in the marked areas of both types of electroetched samples. Chromium, resulting from the corrosion inhibitor in the electroetchants, was found in the etched areas as well as on the coupon away from the electroetched areas. Depth profile data indicated that the major etching action (marking thickness) of the electroetchants penetrated to a depth of approximately 200 nm. Trace amounts of chlorine were present primarily within the first 65 nm of the marked surface. Comparison of the solvent rinsing sequences revealed that the most effective cleaning process included a degreaser, such as perchloroethylene, followed by a polar solvent, such as alcohol. Evaluation of the use of an abrasive cleaner on the electroetched areas indicates that this process removed residual contaminants, increased mark legibility and did not introduce significant residuals from the abrading material or cause significant surface damage.

Quantitative gas chromatographic analysis of boron trichloride, boron and boron nitride

The quantitative on-line analysis of the gaseous products of a nitrogen plasma jet, containing trace amounts of chlorine and boron trichloride, has been carried out. The quantitative analysis of the solid products, boron and boron nitride, has also been carried out by in situ reaction with chlorine followed by gas chromatography. The chlorine attacks the boron and the boron nitride in a specially designed reaction—injection system of the gas chromatography at 500° for a 1-min period. Then, the reaction products are immediately swept into the column through the gas sampling valve. Both of the analyses are carried out with a 2-m Teflon column containing 10% Kel-F 3 on Teflon 6 at 40°. About 1% (v/v) of boron trichloride vapour is incorporated in the carrier gas so as to prevent irreversible adsorption of the small amount of boron trichloride that is to be detected.