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Buffer solution

About: Buffer solution is a research topic. Over the lifetime, 6948 publications have been published within this topic receiving 112440 citations. The topic is also known as: pH buffer & buffer.


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Journal ArticleDOI
TL;DR: In this article, high active catalysts for electrochemical reduction of oxygen insensitive to the presence of methanol were prepared from transition metal hexacyanometallate precursors by heat-treatment with carbon black under an inert atmosphere.
Abstract: Highly active catalysts for electrochemical reduction of oxygen insensitive to the presence of methanol were prepared from transition metal hexacyanometallate precursors by heat-treatment with carbon black under an inert atmosphere. The catalytic activity for oxygen reduction was examined with the floating electrode technique under an air atmosphere at room temperature. The electrolyte used in most of the measurements was 1 M sodium phosphate buffer solution (pH 7.5), whereas acid and alkaline solutions were also used in addition to the neutral buffer solution to examine the catalytic activity of the prepared catalyst over a wide range of pH. Remarkable enhancements in the catalytic activity were observed for samples heat-treated at temperatures higher than 500°C. Among several 3d-transition metals incorporated in the inorganic precursor, the combination of cobalt and iron incorporated at neighboring sites gave the highest activity, comparable to that of platinum black catalyst (Pt/C). The catalytic activity for oxygen reduction was not affected by the presence of 2.5 M methanol in the electrolyte, while that of Pt/C was severely impaired by the presence of methanol. The catalysts prepared from the inorganic precursors were characterized by X-ray diffraction (XRD), infrared (IR), and X-ray photoelectron spectroscopy (XPS) measurements. The XRD and IR data indicated that the cyanide structure of the inorganic precursor was decomposed when heating beyond 500°C. The XPS data indicated that the oxidation states of cobalt and iron are close to metallic ones and two types of nitrogen forming new bonding are present in the heat-treated samples. The same structural and spectral changes were observed for samples heat-treated without carbon black. From these results, the evolution of the high catalytic activity by heat-treating the inorganic precursors is discussed.

76 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of buffers and pH on the thermal resistance of a flat sour-type of spoilage bacterium,Alicyclobacillus acidoterrestris, was investigated.

76 citations

Journal ArticleDOI
TL;DR: The successful determination of the concentrations of H2S in local air indicates the potential application of this cost-effective method and exhibits excellent visual sensitivity with a naked-eye detectable limit of 0.5 ppm (v/v), making the on-site detection of H1S possible.
Abstract: We have described a simple and low-cost visual method for on-site detection of hydrogen sulfide (H2S) in air based on the antiaggregation of gold nanoparticles (AuNPs). The bubbling of H2S into a weak alkaline buffer solution leads to the formation of HS–, which can stabilize the AuNPs and ensure the AuNPs maintain their red color even in a Tris buffer solution containing 80 mM NaCl with the presence of Tween 80. The stabilization of the AuNPs is attributed to the adsorption of negatively charged S2– on the AuNPs surface. In contrast, without the bubbling of H2S, AuNPs aggregate and change color from red to blue. Under optimal conditions, the proposed method exhibits excellent visual sensitivity with a naked-eye detectable limit of 0.5 ppm (v/v), making the on-site detection of H2S possible. This method also possesses good selectivity toward H2S over other gases by using a simple SO2 removal device. The successful determination of the concentrations of H2S in local air indicates the potential application ...

76 citations

Journal ArticleDOI
TL;DR: A new kind of electroactive polymers was synthesized by using aniline pentamer (AP) cross-linking chitosan (CS) in acetic acid/DMSO/DMF solution and showed an obvious improvement in inducing PC-12 differentiation, while PC- 12 on pure CS films had only little neurites on the fifth day.

76 citations

Journal ArticleDOI
TL;DR: Equations are proposed to relate pH and buffer capacity change of these buffers to the initial aqueous pH value and to the volume fraction of acetonitrile added and this prediction allows estimation of the retention of an acid/base compound in a particular aconetitrile-water buffered mobile phase.
Abstract: The addition of acetonitrile to aqueous buffers to prepare RP HPLC mobile phases changes the buffer properties (pH and buffer capacity). This variation is studied for acetate, phosphate, phthalate,...

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202317
202232
202185
2020151
2019220
2018245