Effect of pH buffering

Tran, A. D., Park, S., Lisi, P. J., Huynh, O. T., Ryall, R. R., and Lane, P. A., Separation of carbohydrate-mediated microheterogeneity of recombinant human erythropoietin by free solution capillary electrophoresis. Effects of pH, buffer type and organic additives,. Ckromatogr., 542, 459, 1991. 

Powell, M. F. (1986), Enhanced stability of codeine sulfate Effect of pH, buffer, and temperature on the degradation of codeine in aqueous solution,/. Pharm. Sci.,75, 901. 

Effects of pH, buffer composition and temperature on reaction rates of enzymes... 

Photodegradation process This part of study was consisted of a preliminary test and a further photodegradation test. The preliminary test was to examine the basic photodegradaton of sixteen commercial dyes while the further photodegradation test was to explore the reaction pathways and the decay rates of six purified Aromatic Dyes under different conditions. These conditions were aimed at studying including 1) the effect of initial pH 2) the effect of pH buffer 3) the quenching effect in the... 

Figure 8. Results of a geochemical model investigating the effects of pH buffering by acetic acid-acetate on the response of the carbonate system to changes in pCO. Increases in the pC02 of calcite-saturated solutions will promote calcite undersaturation for initial concentrations of acetic acid up to approximately 0.06 m (3600 mg/I). This is called the crossover concentration. (Reproduced with permission from Ref. 7. Copyright 1989 Elsevier).

The degradation kinetics of vincristine sulfate (1) and vindesine sulfate (11) in the pH range from —2 to 11 at 80 ° C were studied, and the effects of pH, buffer concentrations, ionic strength, and temperature were considered. The relationship between pH and log kobs was modeled by using a non-linear least squares curve fitting computer program. From dris plot pJCa values of II were calculated."... 

Acetate buffer (Park et al., 2007) and carbonate buffer solutions (Ko, Schlautman, and Carraway, 2000) have often been used to enhance electroosmotic flow in surfactant or cyclodextrin-enhanced electrokinetic systems. The effect of pH buffer is more clearly seen in soils of low carbonate content pH control significantly improves electroosmotic flow under such conditions. However, it was reported that a combination of buffer solution with a surfactant/cosolvent solution only marginally improved electroosmotic flow (Saichek, 2002). Consequently, pH control should be considered together with other variables influencing electroosmotic flow. 

Figure 6.3 Effect of pH buffered solutions (5.4, 7.4 and 9.4) on the integrity of blank (a), 6 wt% (b) and 10 wt% (c) hydrogel over 30 days. Reproduced with permission from R.T.C. Cleophas, J. Sjollema, H.J. Busscher, J.A.W. Kruijtzer and R.M.J. Liskamp, Biomacromolecules, 2014, 15, 3390. 2014, American Chemical...

The present study represents a full characterization of the effects of pH, buffer concentration, and monoanions on the hydration and dehydration activity of BCA, studied by the method of initial rates using stopped-flow techniques. The results of this study impose further constraints on acceptable mechanisms for carbonic anhydrase activity. We propose a kinetic rationalization and a mechanistic scheme consistent with the data presented. 

It is worth to notice, that this cahbiation curve is obtained for SNARF-1 dextran/ urease capsule in pure water without substantial contamination of aity salt, which could bulFer the systems and spoil truly picture for urea detection. We carried out experiments to build a similar calibration curve in the presence of the 0.001 M TRIS-maleate buffer (were used solutions with the pH 6.5 and 7.5) but it resulted in overwhelming effect of pH buffering. Buffering the solution eliminates the pH change caused in a course of enzymatic reactions. Thus, it sets a hmit for detection of urea concentration using SNARF-l-dextran/urease capsules. However the calibration in conditions of particular experimental system is reasonable at salt free solution assumption. Summarizing, one can state the presented in Fig. 20.7 calibration curve as suitable for estimation of urea concentrations in-situ in water solutions. 

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