Bicarbonate buffer

Aldehydes can be dkeedy converted to esters using bromine in alcohol solvents with sodium bicarbonate buffer (41). 

X 10 M), and an equivalent amount of OH (its usual concentration in plasma) would swamp the buffer system, causing a dangerous rise in the plasma pH. How, then, can this bicarbonate system function effectively The bicarbonate buffer system works well because the critical concentration of H2CO3 is maintained relatively constant through equilibrium with dissolved CO2 produced in the tissues and available as a gaseous CO2 reservoir in the lungs. ... 

Under the conditions of temperature and ionic strength prevailing in mammalian body fluids, the equilibrium for this reaction lies far to the left, such that about 500 CO2 molecules are present in solution for every molecule of H2CO3. Because dissolved CO2 and H2CO3 are in equilibrium, the proper expression for H2CO3 availability is [C02(d)] + [H2CO3], the so-called total carbonic acid pool, consisting primarily of C02(d). The overall equilibrium for the bicarbonate buffer system then is... 

Palaghias, G. The Role of Phosphate and Carbonic Acid-bicarbonate Buffers in the Corrosion Processes of the Oral Cavity , Dental Materials, 1, 139-144 (1985)... 

Danckwerts et al. (D6, R4, R5) recently used the absorption of COz in carbonate-bicarbonate buffer solutions containing arsenate as a catalyst in the study of absorption in packed column. The C02 undergoes a pseudo first-order reaction and the reaction rate constant is well defined. Consequently this reaction could prove to be a useful method for determining mass-transfer rates and evaluating the reliability of analytical approaches proposed for the prediction of mass transfer with simultaneous chemical reaction in gas-liquid dispersions. 

Allow to react at the start with 0 05% dansyl chlonde solution in hexane, dry and expose for 10 h to the vapors of a tnethylamme bicarbonate buffer (c = 0 1 mol/l, pH 8 5), then develop Ex cess reagent and by-products run with the solvent front... 

NOTE P2 synaptosomes were incubated in a ICrebs Ringer bicarbonate buffer for 2 hours at 37 °C. The frozen control was not incubated. Values for MDMA-treated samples are given as a percent of the incubated control SEM. 

Methanogenesis Co2+ 40 pM Methanosarcina sp. Mineral salts medium containing bicarbonate buffer and 1 mM sulfur 66... 

Dissolve TNBS in 0.1M sodium bicarbonate, pH 8.5, at a concentration of 0.01 percent (w/v). Prepare fresh. Note TNBS may be prepared as a stock solution in ethanol at a concentration of 1.5 percent. This solution is stable to long-term storage and may be diluted as needed in the bicarbonate buffer to the required concentration. 

Tris), since these will cross-react with the imidoester groups. Borate or bicarbonate buffers adjusted to the optimum pH range work well. The addition of (or the exclusive use of) 0.1-0.2 M triethanolamine is often done to help catalyze the coupling reaction. 

Dissolve the amine-containing macromolecule to be labeled (i.e., a protein) in 0.1M sodium carbonate/bicarbonate buffer, pH 9.0, at a concentration of l-5mg/ml. 

Dissolve a first protein to be modified at a concentration of l-10mg/ml in 0.1 M sodium bicarbonate buffer, pH 8.5. PBS buffer at physiological pH also may be used as the reaction medium. 

This reaction is essential in maintaining a constant pH in blood by the bicarbonate buffer system. Carbonic anhydrase, which contains a single zinc atom in its structure, has a molecular weight of about 30,000. In this structure, zinc is surrounded tetrahedrally by three histidine molecules and one water molecule. The exact role of the catalyst is not known, but it is believed to involve hydrolysis that can be represented as... 

Fermentation of D-xylose by Escherichia coli at pH 5.5 (in bicarbonate buffer) gives more than one mole of lactic acid per mole because of fixation of carbon dioxide by the two-carbon fragment,198(a> an observation that may have an important bearing on theories of photosynthetic fixation of carbon dioxide.198[Pg.223]

Henderson-Hasselbalch Equation Titration Curves p/—Isoelectric Point The Bicarbonate Buffer Imbalance in Blood pH Acidosis and Alkalosis... 

The C02-bicarbonate buffer is a little different from buffers using the usual kind of acids and bases, but it is extremely important in maintaining the acid-base balance of the blood. The acid form of the bicarbonate buffer is actually a gas dissolved in water. Dissolved C02 is turned into an acid by hydration to give H2C03. Hydrated C02 is then much like a carboxylic acid. It gives up a proton to a base and makes bicarbonate, HCO 3. 

There are two ways of dealing with the bicarbonate buffer system. The first uses the Henderson-Hasselbalch equation and an effective pKa of 6.1. If there is more base (HCO 3) than acid (C02), the pH will always be bigger than the pKa. This is usually the case physiologically (pH = 7.4 pKa = 6.1) so that on a molar basis there is always more than 10-fold more HCO 3 than C02. 

You might be wondering why the bicarbonate buffer can buffer effectively at pH 7.4 when its pKa is 6.1. The answer is that it doesn t buffer all that well. What makes it unique and the major buffer system of the blood is that C02, being a gas, can be exhaled by the lungs. Exhaling C02 is equivalent to exhaling protons. 

Developed by the US company, Isis, Vitravene is used to treat cytomegalovirus (CMV) retinitis in AIDS patients. It is synthesized chemically and formulated as a sterile solution (6.6 mg active drug/ml) in WFI using a bicarbonate buffer to maintain a final product pH of 8.7. 

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