Boric acid, buffer

Fig ure 3. Starch gel electrophoresis of hemoglobins. Tris-EDTA-boric acid buffer, pH 9.0. O-Dianisidine stain. 

The presence of Individual chains In a hemoglobin variant can also be demonstrated by electrophoresis at alkaline pH after the protein has been dissociated Into Its subunits through exposure to 6 M urea In the presence of 3-mercaptoethanol. The buffer is either a barbital buffer or a tris-EDTA-boric acid buffer, pH 8.0 - 8.6, and contains 6 M urea and 3-niercapto-ethanol. Dissociation of the hemoglobin Into subunits Is best accomplished In a mixture of 1 ml 10 g% Hb (or whole hemolysate), 4 ml 6 M urea barbital or tris-EDTA-boric acid buffer, and 1 to 1.5 ml 3-mercaptoethanol. After 30 minutes to 1 hour the sample Is subjected to cellulose acetate or starch gel electrophoresis. Each chain has a specific mobility and an alteration In electrophoretic mobility easily Identifies the abnormal chain. 

Vinas et al. [46] also determined penicillamine by chemiluminescence - flow injection analysis. The sample was dissolved in water, and a portion of resulting solution was introduced into an FIA system consisting of 5 mM luminol in 0.1 M KOH-boric acid buffer (pH 10.4), 50 pM Cu(II), and 10 mM H202 eluted at 7.2 mL/min. Chemiluminescent detection was used, the calibration graphs were linear from 0.1 to 10 mM of penicillamine, and the coefficients of variation were from 1.2% and 2.1%i. 

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. 

The monograph of levocarbastine has already been revised. The determination of the related substances is performed by means of MEKC using an electrolyte solution composed of sodium dodecyl sulfate as a micelle-forming agent in addition to hydroxypropyl-/ -cyclodextrin in a boric acid buffer of pH 9.0. Due to the very good specificity and robustness the method is able to baseline separate the nine specified and detectable impurities and the drug substance. It is easy to meet the system suitability (Rs>4) the resolution between levocarbastine and impurity D was found to be 6.4 and the content of related substances less than 0.5% (see Figure lA and B). 

There are a number of factors that may also affect the solution pH such as temperature, ionic strength, dilution, and the amount and type of cosolvents present. For example, the pH of acetate buffers is known to increase with temperature, whereas the pH of boric acid buffers decreases with temperature. Finally, the drug in solution may itself act as a buffer. If the drug is a weak electrolyte, such as salicylic acid or ephedrine, the addition of base or acid, respectively, will create a system in which the drug can act as a buffer. 

Another successful example is the separation of a series of steroids listed in Fig. 6.11 using a monolithic capillary column prepared by redox initiated polymerization of a solution of acrylamide 4, methylene bisacrylamide 5, vinylsulfonic acid 12, and dodecyl acrylate 18 in N-methylformamide/TRIS-boric acid buffer (pH 8.2) to which polyethylene glycol) (MW 10,000) was added (overall composition 5% T, 60% C, 10% vinylsulfonic acid, 15% lauryl acrylate, 3% polyethylene glycol)). The capillary tube was first vinylized and its part beyond the detection window was coated with linear polyacrylamide to avoid band broadening. Since laser induced fluorescence was used to decrease the detection limit of the method to about 100 attomoles for neutral steroids, all of the analytes were first tagged with dansylhydrazine. Fig. 6.12 shows an... 

Dansylated amino acids P-Cyclodextrin-bonded positively charged polyacrylamide gel 200 mMTris, 300 mM boric acid buffer, pH 8.1 550-700 mm x 75 pm i.d. 350 mm effective length, chiral separation... 

Figure 6.3 Schematic of anodic polarization curve of iron,10 showing active-passive behavior of iron in sodium borate-boric acid buffer solution at pH 8.4...

These ethers can also be converted into methyl ethers in high yield by nickel boride (5, 472) in boric acid buffer. Ester and acetal groups are stable under these conditions. Raney nickel is less useful for this desulfurization because of erratic results. 

The borate buffer is necessary to complex the neutral carbohydrates to give them ionic properties that then allow separation by anion exchange chromatography. A sodium tetraborate-boric acid buffer (pH 8.5) whose composition varies from 0.169 to 0.845 Af in the borate ion is used as the eluent. The anion exchange separation column is maintained at a constant 55°C. 

Fig. 13. Starch gel electrophoresis of hemoglobin of cord blood samples from newborns with various types of a-thalassemia. Tris-EDTA-boric acid buffer, pH 8.6. Stained with o-dianisidine. From Pootrakul et al. (P22) with permission of the authors and publisher.

Fig. 15. Horizontal starch gel electrophoresis to show the small differences in mobility between three fetal hemoglobin variants. Left to right (1) Hb-F-Malta-I heterozygote, (2) and (3) normal adults (4) Hb-Fx in a Negro newborn (5) Hb-F-Malta-II heterozygote (6), (7), and (8), Hb-A, Hb-F, and Hb-F-Malta-II fractions, respectively, isolated by column chromatography on CM-cellulose. Tris-EDTA-boric acid buffer, pH 9.0, o-dianisidine stain.

FIG. 13 Log-log plot of the binding isotherms of amphiphilic proteins to amphiphilic poly anions. ( , o) /3-lactoglobulin to copolymer of maleic acid and octyl- or dodecyl vinylether, respectively pH 8.7 and ionic strength 0.1 M (data from Ref. 50). (0, , A) bovine serum albumin to C18 modified poly(acrylic acid), pH 9.0 in 30 mM NaOH-boric acid buffer. Modification rate 10, 3, and 1 mol% respectively (data from Ref. 63). Free protein in /rniol/L protein/polymer ratio in number of protein globules per 1000 monomers. 

However, it is worth noting that while the Swedish warship Vasa is still contaminated with sulfur and generating acid, it is now apparent that during its treatment by spraying a considerable amount of acid was generated, as the pH of the spray solution kept falling. This was neutralised by the addition of borax/boric acid buffer. In the case of the Vasa, the major sulfur contaminant appears to be elemental sulfur that is essentially insoluble in water. However,... 

For Curve B the solution was sodium chloride-boric acid buffered to pH 7.8. The polarization conditions were the same. However in the presence of the chloride the maximum current before the onset of passivity was increased and the potential range for passivity was decreased. The high currents observed in the "passive region" were mainly due to localized attack which leads to pitting. The major part of the surface is still covered by the same type of iron oxide film as that found with the pure borate buffer. 

Tin ions are reduced to tin hydride from a boric-acid-buffered medium by means of sodium borohydride, transferred to a heated quartz cuvette by a current of inert gas, decomposed thermally, and the absorption of the atoms is measured in the beam of an atomic-absorption spectrometer. In the hydride technique, the element which is to be determined is volatilized as a gaseous hydride and in this way separated off from the matrix. Interference may occur if there is a considerable excess of elements such as antimony, arsenic, bismuth, mercury, selenium or tellurium which can also be volatilized with this technique. Above all, heavy metals such as copper and nickel in the solution have a disturbing effect during hydride formation itself. Interference due to phosphoric acid and hydrochloric acid may also be observed. It is therefore vital to check the method by the addition technique. 

Fig. 4 The separation of free dye and protein-dye complex by micro-chip NECEEM. a, BSA-Red-lc complex. Sample and experimental details Precolumn labeling of 0.50 p,mol BSA with 5.0 p,mol Red-lc 60 sec injection 2500 V separation voltage 6 mm effective separation channel length 800 V PMT voltage b, p-lactoglobulin B-Red-lc complex. Sample and experimental details Precolumn labeling of 75 p,mol P-lactoglo-bulin B with 5.0 xmol Red-lc 10 mm effective separation channel length 100 mmol boric acid buffer (pH 9.5) with 100 mmol KCl.

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