Applications of pH Buffers

V. Baelum, O. Fejerskov, A. Kuseler, Approximal plaque pH follow/ing topical applications of standard buffers in vivo. Caries Res. 28 (1994) 116-122. 

The second novelty of our work is the elucidation of the role of pH-buffers in swelling equilibria and kinetics. It is interesting to note that most physical chemists choose not to use buffers because they complicate the system under study. On the other hand, any ultimate biological application of gels is likely to involve some sort of buffered medium. As we have shown, buffer properties such... 

Another application of pH-stats is to control solution pH without the use of a buffer system. Again, this can be accomplished by either a burette delivery system, a motor-driven syringe, or electrochemical generation of hydroxide ion or hydronium ion. This can be extremely useful for systems where all available buffer solutions interfere with the reaction of interest. 

Chuang CY, Chiu WY, Don TM (2011) Synthesis of chitosan-poly(acrylic acid) complex particles by dispersion polymerization and their applications in ph buffering and drug release. J Appl Polym Sci 120(3) 1659-1670... 

Concentration limits of the diphosphate-ion, admissible to determination of magnesium and cobalt, manganese and cobalt, zinc and cobalt by spectrophotometric method with application of the l-(2-pyridylazo)-resorcinol (PAR) are presented. Exceeding maintenance of the diphosphate-ion higher admissible supposes a preliminary its separation on the anionite in the H+-form. The optimum conditions of cobalt determination and amount of the PAR, necessary for its full fastening are established on foundation of dependence of optical density of the cobalt complex with PAR from concentration Co + and pH (buffer solutions citrate-ammoniac and acetate-ammoniac). 

Equation 141 is a completely general equation, applicable to all buffer systems. The calculation of [H+]—and hence pH—can be simplified if you keep two points in mind. 

Some applications of buffers. Many products, including aspirin and blood plasma, are buffered. Buffer tablets are also available in the laboratory (far right to make up a solution to a specified pH. 

Buffer solutions find many applications in quantitative analysis, e.g. many precipitations are quantitative only under carefully controlled conditions of pH, as are also many compleximetric titrations numerous examples of their use will be found throughout the book. 

Solochrome dark blue or calcon ( C.1.15705). This is sometimes referred to as eriochrome blue black RC it is in fact sodium l-(2-hydroxy-l-naphthylazo)-2-naphthol-4-sulphonate. The dyestuff has two ionisable phenolic hydrogen atoms the protons ionise stepwise with pK values of 7.4 and 13.5 respectively. An important application of the indicator is in the complexometric titration of calcium in the presence of magnesium this must be carried out at a pH of about 12.3 (obtained, for example, with a diethylamine buffer 5 mL for every 100 mL of solution) in order to avoid the interference of magnesium. Under these conditions magnesium is precipitated quantitatively as the hydroxide. The colour change is from pink to pure blue. 

Fig. 8. Preparative isolation of hexon antigen of EDS-76 by hydrophobic-interaction chromatography on Butyl-PG column (2x5 cm) (A) application of the allantoic fluid diluted (1 5) by 50 mM potassium acetate, pH 4,130 ml (B)0.01 mol/1 potassium acetate, pH 5.5 (C) 0.01 mol/1 potassium bicarbonate pH 8.0, 10% isopropanol (D) 0.01 mol/1 potassium carbonate pH 9.6, 10% isopropanol. EDS-0 — components of alantoic fluid eluted with buffer A, EDS-1 — desorbed hexon fraction eluted with buffer C, EDS-2 — fraction desorbed with buffer D [56]...

The common-ion effect is quite general. The chemistry of buffer solutions is another important application of this principle. A buffer solution relies on the common-ion effect to suppress the concentration of hydronium ions and maintain a steady pH ... 

Avdeef and Bucher [24] investigated the use of universal buffers in potentiomet-ric titrations. Recently, such a buffer system, formulated with several of the Good components, has been designed specifically for robotic applications, where automated pH control in 96-well microtiter plates is required, with minimal interference to the UV measurement [48]. This universal buffer has a nearly perfectly linear pH response to additions of standard titrant in the pH 3-10 region [8, 48]. 

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