213 research outputs found
Determination of Standard pH Values for Potassium Hydrogenphthalate Reference Buffer Solutions in 10, 20, 50 64 and 84.2 wt per cent Methanol/Water Mixed Sovents at Temperatures from 283.15 to 313.15 K
No full textStandard pH0 values for 0.05 mol kg-1 potassium phthalate reference buffer solutions in 10, 20, 50, 64 and 84.2 wt % methanol/water solvent mixtures have been obtained from cells without transport, in the temperature range 283.15-313.15 K. The consistency of results has been analysed by a new method of multilinear regression of the quantity p(aHγCl) as a function of both temperature and solution composition. The pH° values found can be reproduced within ± 0.01 by the equation pH0 = 4.00 + 4.38x - 5.02x2 + 4.23x3 + 0.13z - 0.91xz, where x = mole fraction of methanol in the solvent mixture, z = (T - θ)/θ and θ = 298.15 K. Subsidiary values of the first ionization constant of o-phthalic acid in the above solvent mixtures have also been obtained by the buffered cell method
Criteria for Standardization of pH Measurements in Organic Solvents and Water + Organic Solvent Mixtures of Moderate to High Permittivities
No full textpH standardization in aqueous solutions may now be considered as substantially achieved. The experimental work done so far in pioneering pH standardization in nonaqueous and mixed solvents, an extension which is very important for chemistry and chemical engineering, though based on sound physicochemical principles is regrettably fragmentary and scarce. Systematic acquisition of data is urgently needed for many important media, although the field is apparently almost unlimited. Doing this without valid and recognized objectives might clearly result in a disorienting and chaotic situation. This paper defines as many pH standards, pH//S, as necessary to cover the normal scale length of pH in each solvent, within the usual range of temperatures. This requires the appropriate experimental work and an extra-thermodynamic procedure, which is a logical extension of what is now endorsed, and currently applied, in the case of aqueous solutions
Analytical and Biomedical Applications of Ion-Selective Field-Effect Transistors (Wilson and Wilson's Comprehensive Analytical Chemistry, Volume XXIII)
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The design of cells with liquid junctions and the elimination of the liquid junction potential
No full textIon Chromatography with Ion-Selective Electrode Detectors and Its Environmental Applications
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