Sodium acetate borate

Buffers contain mixtures of weak acids and their salts (i.e., the conjugate bases of acids), or mixtures of weak bases and their conjugate acids. Typical buffer systems used in pharmaceutical dosage forms include mixtures of boric acid and sodium borate, acetic acid and sodium acetate, and sodium acid phosphate and disodium phosphate. The reason for the buffering action of a weak acid, HA (e.g., acetic acid) and its ionized salt, A" (e.g., sodium acetate) is that A" ions from the salt combine with the added hydrogen ions, removing them from solution as undissociated weak acid. 

A mixture consisting of 25 mL of an aqueous (0.2 to 1.0 mM) solution of chlorpromazine hydrochloride and 5 mL of 0.1 M acetate buffer (pH 3.3) was titrated to a potentiometric endpoint with 0.0 IM sodium tetraphenyl-borate [77]. The titrant was added at a rate of 0.36 mL/min with continuous stirring, and the temperature of the medium was maintained at 22 2°C. The end point was detected by a tetraphenylborate-selective electrode. 

Reaction of B20(0Ac)4 with sodium acetate results in the formation of Na[B20(0Ac)5] with O and OAc bridges, whereas acetatoborates, M[B(OAc)4] (M = K, Rb, Cs, Tl), are obtained when the reaction is conducted in the presence of acetic anhydride. These borates are easily hydrolyzed in the case of [B(OAc)4]- the rate determining step seems to be dissociation of the complex. Binuclear "borates M2[B20(0Ac)6] and M2[B202(0Ac)4], were detected, inter alia, during thermal decomposition of tetraacetatoborates.132 The crystal structure of K[B(OAc)4] has been determined.133... 

Paper partition chromatographic methods have been widely applied to the analysis of tetracyclines (128, 129). Pharmaceutical aqueous suspensions for oral use are acidified with HC1 and diluted with methanol. Crystalline formulations are dissolved only in methanol. A paper chromatographic method for TC determination in pharmaceutical preparations is based on the complexation of the antibiotic with a mixture of urea and disodium edetate on paper at pH 7.4. Urea helped in the separation of degradation products and led to the formation of well defined spots (130). Samples from fermentations must be acidified with oxalic acid to liberate TC from the mycelium. TC in filtrates may be precipitated in saturated solution of sodium tetraphenyl borate, precipitate dissolved in ethyl or butyl acetate and applied for paper chromatography. Various solvent systems and hRp values for paper chromatography are given in Table 4. 

Effect of pH on the addition reactions was studied from pH 4 to 10. For pH values below 7, the reaction was buffered with a 25 mM sodium acetate solution whereas for pH values above 7, a 25 mM disodium tetraborate solution was used the pH was adjusted by adding either HC1 or NaOH. The combination electrode used for the determination of experimental pH, was calibrated with National Bureau of Standards (NBS) buffers for Milli-Q water (36) and tris(hydroxymethyl)aminomethane (TRIS) buffers for seawater (37) and NaCl solutions (38) on the pHF (free proton) scale. Since the addition of reactants caused a small pH change in the buffered medium, the experimental pH values shown in the results were measured after the reactants were added to reaction bottle. Samples from low pH reaction series were adjusted topH 9 by addition of a strong borate buffer just prior to HPLC analysis. Inis was necessary because thiol analysis using o-phthalaldehyde requires this pH for optimum derivatization. 

The piperidine derivative (111) has been reported109 from the reaction of piperidine and 112 in acetic acid with sodium tetraphenyl-borate. The piperidine derivative (113) arises from a displacement of... 

The reaction of bis(phenylsulfanyl)alkyllithiums with trialkylboranes provides the adduct 144, after elimination of phenylsulfanyllithium. Final oxidation with hydrogen peroxide-dioxane in aqueous sodium acetate afforded aldehydes or ketones in good yields (Scheme 40)151,152. However, this process cannot be carried out with 2-lithio-l,3-dithiane because the initially formed borate did not undergo the spontaneous alkyl migration reaction152. 

Sodium borohydride 10 mg/mL, freshly prepared in 10 mMNaOH. Acetate-buffered saline 50 mM sodium acetate, 0.9% NaCl, pH 4.5. Borate-buffered saline O.lMsodium borate, 0.9% NaCl, pH 8.5. 

A standard non-aqueous CE method for the analysis of acidic solutes [23] has been demonstrated. This employs 10 mM sodium acetate dissolved in 50 50 methanol-acetonitrile. Fig. 3.13 shows the separation of a range of acids using this method. The selectivity obtained was markedly different from the same separation obtained using the standard aqueous high-pH borate buffer. 

Purine itself, on macroscale reduction at a mercury cathode in acetic or hydrochloric acid, is reduced to 1,6-dihydropurine, isolated as a complex with sodium tetraphenyl borate. ... 

A solution of hypochlorite is stable in an excess of alkali, whereas in acid there is a slow conversion to chlorate. The minimum stability of hypochlorite solutions is at pH 6.7 (6.68 and 7-7.13 have also been reported - ) and the maximum stability is at pH 13. There is also a region of high stability in strong acid, where the solute is predominantly composed of chlorine and only very little hypochlorous acid. The rate of decomposition at pH 6.7-7.2 is proportional to the chloride concentration and to the square of the hypochlorite concentration. In slightly alkaline solution the rate is proportional to [0C1-][H0C1]. The catalytic effect of chloride ion is well known buffers " such as acetate, borate and carbonate also have an effect. It has been recommended that the concentration of phosphate buffers be kept below 0.25 M to prevent decomposition of hypochlorite solutions. The catalytic effect of heavy metals, especially copper and iron, has been noted. The effect of various cations is shown in the greater stability of lithium hypochlorite in comparison with the sodium and potassium salts. ... 

Chloroprene Delrin 500F Texin 480AR Lead Chloride Sodium Thioarsenate Sodium Thioarsenate Sodium Thioarsenate Dowfax 2A1 Silicate Aroclor 5442 Lead Bromide Potassium Perborate Aroclor 1248 Potassium Borate Sodium Chromate Potassium Acetate Sodium Acetate Pyruvic Acid Perchloroethylene Perclene Tetrach loroethylene Dimethylacetamide Dimethyl Acetamide (N.N-) Methyl Abietate Aktivin... 

A variety of regulatory approved buffers are available covering the useful pH range. For acidic pH adjustment, acetic acid/sodium acetate or citric acid/sodium citrate are often employed. For alkaline-buffered solutions, phosphate or borate buffers are frequently used. 

Purified oligonucleotides (80-100 nmol) were dissolved in 0.1 mL of 20 mM sodium acetate (pH 4.4) and 4.6 /jumol of sodium metaperiodate was added. The reaction was stirred for 30 min at 0°C in the dark. An equal volume of poly-Lys (Sigma, mean 15 kd) 80-100 nmol in 2 M NaCl, 0.2 M sodium borate buffer (pH 8.4), and 100 /miol sodium cyanoborohydride were added. The mixture was incubated overnight at 20°C and then loaded on a Sephadex G-50 column equilibrated with 0.5 M NaCl, 20 mM sodium acetate buffer (pH 6.0). Each fraction was assayed for its oligonucleotide-poly-Lys content by absorbance at 260 nm and by protein assay. The conjugates were stored at — 80°C. 

Plating solution, chrome Potassium acid sulfate Potassum alum Potassum aluminum sulfate Potassium bicarbonate Potassium bichromate Potassium bifluoride Potassium bisulfate Potassium bisulfite Potassium bitartrate Potassium bromide Potassium carbonate Potassium chlorate Potassium chloride Potassium chromates Potassium citrate Potassium cyanate Silicone tetrachloride, dry Silicone tetrachloride, wet Silver bromide Silver chloride Silver cyanide Silver nitrate Silver sulfate Soap solutions Soda ash Sodium acetate Sodium benzoate Sodium bicarbonate Sodium bichromate Sodium bifluoride Sodium bisulfate Sodium bisulfide Sodium bisulfite Sodium borate Sodium bromate Sodium bromide Sodium carbonate... 

Lyophilize the purified end-labeled DNA that contains chloroacetaldehyde-modified MAR sequences at equal quantity in two separate Eppendorf tubes one for the hydrazine reaction and the other for the formic acid reaction. The step-by-step procedures for hydrazine and formic acid reactions for Maxam-Gilbert reactions are described in Sambrook et al. (1989). We have made the following deviations (a) the temperature employed for chemical reactions is 15°C instead of 20°C (b) at each step of precipitation of DNA with ethanol, there is no need to chill at -70°C before centrifugation and DNA is centrifuged at 10,000 g for 10 min at 4°C after the piperidine reaction, the sample is transferred to a new tube that contains 100 fi of 0.6 M sodium acetate at pH 5 in TE (10 mAf Tris-HCl, pH 7.5, 1 mAf EDTA) and precipitated with three volumes of ethanol. Redissolve the DNA pellet in 200 fi of 0.3 M sodium acetate and reprecipitate with ethanol. Wash the DNA pellet once with 70% ethanol, and lyophilize. Resuspend the DNA samples in 90% formamide in 1 x TBE (89 mAf Tris-borate, 89 mAf boric acid, 2 mAf EDTA) loading buffer, heat at 95 C for 5 min followed by quick chilling on ice. Separate the DNA samples on a polyacrylamide gel in 8.3 M urea, 100 mAf Tris-borate, pH 8.3, and 2 mAf EDTA. For best visualization of approximately 100-200 base pairs from the labeled end, 6% polyacrylamide gel is recommended. For visualizing 30-100 base pairs, an 8-10% polyacrylamide gel is typically used. 

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