Buffers, boric-borate

Fig. 6. Ratio of steady-state current densities at LaNi03 and platinum for the Fe(EDTA) redox system in boric-borate buffer of pH 8.4 as a function of electrode potential [48],...

Recently, it was been found that RhuA accepts DHA in the presence of boric-borate buffer, presumably by reversible in situ formation of DHA borate ester [39]. Most recently, the group of Wong selected an RhuA mutant enzyme that accepts DHA as a donor [40],... 

In Fig. 9 three polarization curves for iron in buffered sodium borate solutions are shown. In A the solution was sodium borate-boric acid at a pH of 8.4. The curve was obtained by... 

Reagents Borate buffer—Boric acid, 2-76 g, N sodium hydroxide, 23 -4 ml, water to 100 ml. Glyoxal solution (freshly prepared)— A 0-22 per cent solution of glyoxal sodium bisulphite in water. Gelatin solution (freshly prepared)—To 100 ml of hot water add 1 g of gelatin B.P.y previously broken into small pieces, shake until dissolved and cool. 

From this material, samples are cut and swelled to constant weight in a buffered saline solution prepared from 8.43 g sodium chloride (NaCl), 9.26 g boric acid (H3BO3), 1.0 g sodium borate (Na3B03), and 0.1 g of the disodium salt of the dihydrate of ethylenediaminetetraacetic acid [Na2 EDTA -(/ 0)21 ini L of distilled water. 

When a pH meter was standardized with a boric acid-borate buffer with a pH of 9.40, the cell emf was +0.060 V. When the buffer was replaced with a solution of unknown hydronium ion concentration, the cell emf was +0.22 V. What is the pH of the solution ... 

Figure 11 Separation of anti-inflammatories by CZE at various pHs in a 40-cm polyacrylamide-coated (left) and a 70-cm uncoated (right) capillary Experimental conditions 275 V/cm UV = 215 nm buffers 20 mM borate-100 mM boric acid, pH 8.4 (46 pA) 30 mM phosphate-9 mM borate, pH 7.0 (70 pA) 80 mM MES-30 mM Tris, pH 6.1 (20 pA) peak identification 1 = naproxen, 2 = ibuprofen, 3 = tolmetin. (From Wainwright, A., /. Microcol Sep., 2, 166, 1990. With permission.)...

Fig. 17.11. Bottom CGE separation of components of poly U (sigma) in 25% pluronic F127. Top Note the resolution of two contaminants between each of the oligonucleotides from about 15 to 27 nucleotides long in this expanded section of the bottom electropherogram. Electrophoresis was performed in 25% pluronic F127 in tris-borate-EDTA buffer (90 mM tris, 90 mM boric acid, 2 mM Na EDTA, pH 8.3.) (25°C, 500 V cm-1, effective column length 30 cm). Reprinted with permission from Ref. [82],...

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. 

What molar ratio of acid to salt is required to adjust the pH of a solution to 8.8 using boric acid-sodium borate buffer ... 

What molar ratio of salt/acid (sodium borate to boric acid) is required to prepare a buffer solution having a pH of 9.6 The pKa of boric acid is 9.24 at 25°C. 

Purification of murine antiheparin monoclonal antibody produced in cell culture was monitored by Malsch et al.63 using a CZE method with a borate or boric acid buffer (pH 9) in an uncoated capillary. 

Sodium borate buffer 0.2 M boric acid, 160 uiM NaCl, pH 8.5. 

The two lower pH levels were phosphate buffers whereas the 8.6 buffer consisted of a boric acid, sodium borate system. The buffers showed no reaction with pretreatment chemicals used, and had sufficient buffer capacity to maintain constant pH during experiments of long duration. 

Tris-borate-EDTA (TBE) buffer (lOx solution) 0.89 M TRIZMA base, 0.89 M H3BO3,20 mM EDTA. Per liter 108 g TRIZMA base, 55 g boric acid, 40 ml 0.5 M ethylenedi-aminetetraacetate (EDTA) solution. 

Buffers of boric acid are useful in the pH range 8.5 to 10. Borate has the major disadvantage of complex formation with many metabolites, especially carbohydrates. 

Borate buffer 0. M boric acid solution adjusted to pH 8 0 with NaOH... 

Ophthalmic Granulocyte colony stimulating factor HPLC Borate buffer (1.71 g boric acid/0.265 g borate) H20/100 ml, extract with light petroleum, residue dissolved in EtOH Silica -Hexane-EtOAc (98 2), 1 ml/min 600 nm [509]... 

---