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.

Buffered potassium peroxymonosulfate-acetone epoxidation of α,β-unsaturated acids

Abstract: L'addition de NaHCO 3 au systeme epoxydant du titre permet d'effectuer la reaction a 24-27°C sans avoir besoin de controler le pH et sans effet sur le rendement

Factors affecting the temporal stability of semipermanent bilayer coatings in capillary electrophoresis prepared using double-chained surfactants.

Abstract: Surfactants such as didodecyldimethylammonium bromide (DDAB) adsorb onto fused-silica capillaries to form semipermanent bilayer coatings. However, such coatings must be regenerated between runs to maintain efficiency and reproducibility. In this paper, chemical and physical factors affecting the stability of DDAB coatings are investigated. Chemical factors such as ionic strength and the nature of the buffer anion (e.g., from acetate to phosphate), which decrease the critical micelle concentration of DDAB, improve the coating stability. Increasing buffer pH also increases the coating stability. Finally, reducing the capillary diameter and reducing the volume of buffer flushed through the capillary enhance the coating stability. Using 50 mM acetate, pH 5.0, in a 25-μm-i.d. capillary, cationic proteins were separated with efficiencies of 1.05 million plates/m and a run-to-run migration time reproducibility of 0.6−0.8% RSD for 10 successive runs without regeneration of the DDAB coating between runs.

Controlled release of bovine serum albumin from hydroxyapatite microspheres for protein delivery system

Abstract: Desorption behavior of a model protein (bovine serum albumin, BSA) on commercial hydroxyapatite (HAp) microspheres and its control were investigated for protein delivery system. The desorption behavior related strongly to the phosphate concentration in phosphate buffer solution: the amount of desorbed BSA increased when the phosphate concentration increased. In physiological buffer solution, which contains 10 mM phosphate, the initial burst release of BSA was observed: 70% of BSA was rapidly desorbed after 0.5 h, and 80% after 24 h. In contrast, the extremely low release profile of BSA was observed in distilled water. For the controlled release of BSA in physiological condition, the BSA-loaded HAp microspheres were encapsulated with a biodegradable polymer, poly(lactic acid-co-glycolic acid) (PLGA) by a solid-in oil-in water (S/O/W) emulsion solvent evaporation method. The initial burst was significantly reduced, and the BSA release was remarkably prolonged by the encapsulation.

Selective solid-phase extraction of rare earth elements by the chemically modified Amberlite XAD-4 resin with azacrown ether

Abstract: A selective solid-phase extraction procedure using chemically modified Amberlite XAD-4 with monoaza dibenzo 18-crown-6 ether was investigated for the preconcentration and separation of La(III), Nd(III) and Sm(III) in synthetic solution. Before loading samples on synthesized adsorbent adjust pH 4.5 by suitable buffer solution. The adsorbed rare earth elements were eluted by 2 M hydrochloric acid. Various parameters like preconcentration, breakthrough capacity, flow rate were investigated. The limits of detection ( n = 5) and limits of quantification ( n = 5) for La(III), Nd(III) and Sm(III) were founded 3.9, 4.2 and 7.4 μg L −1 and 13, 15 and 26 μg L −1 , respectively. The eluted metal ions were determined by ICP-AES.