Universal buffer solutions

Avdeef, A., Budier,).). Accurate measurements of the concentration of hydrogen ions with a glass electrode calibrations using the Prideaux and other universal buffer solutions and a... 

A known quantity of sample is added to a known volume of a universal buffer solution of sufficient capacity and of known pH. The amount of sample must be sufficient to cause precipitation to occur in the formed saturated solution. After waiting for a period of time to allow the saturated solution to reach the desired steady state, the solution is filtered to remove the solid and obtain a clear solution, whose spectrum is then taken by the UV spectrophotometer. Mathematical treatment of the spectral data yields the area-under-the-curve of the filtered sample solution, AUQ. 

A 10 mM ionic strength universal buffer mixture, consisting of Good zwitterio-nic buffers, [174] and other components (but free of phosphate and boric acid), is used in the pION apparatus [116,556], The 5-pKa mixture produces a linear response to the addition of base titrant in the pH 3-10 interval, as indicated in Fig. 7.53. The robotic system uses the universal buffer solution for all applications, automatically adjusting the pH with the addition of a standardized KOH solution. The robotic system uses a built-in titrator to standardize the pH mapping operation. 

Table 9 Electronic absorption spectra of 83a, 83c, and 84a in aqueous universal buffer solutions ...

Allen RI, Box KJ, Comer J et al. (1998) Multiwavelength spec-trophotometric determination of acid dissociation constants of ionizable drugs. 17(4-5) 699-712 Avdeef A, Bucher JJ (1978) Accurate measurements of the concentration of hydrogen ions with a glass electrode calibrations using the Prideaux and other universal buffer solutions and a computer-controlled automatic titrator. Anal Chem 50 2137-2142... 

These alkaloids are extracted from animal tissues with the universal buffer solution or with acid solution at pH 4 to 5 (using oxalic or tartaric acid). The alkaloids are then identified micro crystallographically by reaction with Rieneck s salt and by Vitali s reaction (57). 

H. T. S. Britton and R. A. Robinson have introduced several new universal buffer solutions. The following solutions are prepared by addition of 0.2 N sodium hydroxide to a solution which is 0.04 molar with respect to phosphoric, acetic, and boric acids. 

Figure 2. Fluorescence ratio, rp, as a function of a for copolymers in universal buffer solutions containing 0.1 M TMACl (first symbol in parentheses) or 0.1 M LiCl (second symbol in parentheses) (O > ) ethyl ( , ) butyl (X. B) pentyl (A, ) hexyl, high M.W. (V, T ) hexyl, low M.W. (O. ) octyl copolymer. From Reference 4.

Fig. 4 (a) SEM and (b) TEM images of L2-eRuO of 5 % wt. RUCI3 comparison of pH response between a glass pH electrode and an L2"CRuO toward (c) pH values and (d) calibration curve of NaOH and HCl titration in universal buffer solution [20] (Reprinted from Microchimica Acta, 2012. 177(1-2) p. 211-219 with permission from Springer Science and Business Media)... 

The pH sensitivity of such films was tested in universal buffer solutions prepared according to the Perrin and Dempsey prescription [17]. The main solutimi consisted of 0.1 M citric acid, 0.1 M KH2PO4, 0.1 M Na2B407, 0.1 M TRIS, and 0.1 M KCl. pH of the buffer solution was adjusted either with HCl or NaOH to cover the pH range from 2 to 10. 

The standard deviation of the potential of the PEDOT-SSA films, in comparison to a conventional Ag AgCl electrode, measured in the universal buffer solution of pH = 9 during 60 min, did not exceed 0.7 mV. In general, the reproducibility of readouts between three electrodes was better than 10 mV. 

Britton HTS, Robinson RA, (1931) Universal buffer solutions and the dissociation constant of veronal. J Chem Soc 1456-1462... 

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