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Total ionic strength adjustment buffer (TISAB) is a buffer solution which increases the ionic strength of a solution to a relatively high level. This is important for potentiometric measurements, including ion selective electrodes, because they measure the activity of the analyte rather than its concentration. TISAB essentially masks minor ...
The molar ionic strength, I, of a solution is a function of the concentration of all ions present in that solution. [3]= = where one half is because we are including both cations and anions, c i is the molar concentration of ion i (M, mol/L), z i is the charge number of that ion, and the sum is taken over all ions in the solution.
For alkaline buffers, a strong base such as sodium hydroxide may be added. Alternatively, a buffer mixture can be made from a mixture of an acid and its conjugate base. For example, an acetate buffer can be made from a mixture of acetic acid and sodium acetate. Similarly, an alkaline buffer can be made from a mixture of the base and its ...
The program mediates between two terminological concepts: The calculations are performed in the "scientific realm" of thermodynamics (activities, speciation, log K values, ionic strength, etc.). Then, the output is translated into the "language" of common use: molar and mass concentrations, alkalinity, buffer capacities, water hardness ...
They can be used to calculate mixed ion activity coefficients and water activities in solutions of high ionic strength for which the Debye–Hückel theory is no longer adequate. They are more rigorous than the equations of specific ion interaction theory (SIT theory), but Pitzer parameters are more difficult to determine experimentally than ...
For this assumption to be valid, equilibrium constants must be determined in a medium of relatively high ionic strength. Where this is not possible, consideration should be given to possible activity variation. The equilibrium expression above is a function of the concentrations [A], [B] etc. of the chemical species in equilibrium. The ...
The pH (and pK a at ionic strength I≠0) of the buffer solution changes with concentration and temperature, and this effect may be predicted using online calculators. [2] MES is highly soluble in water. The melting point is approx. 300 °C. MES was developed as one of Good's buffers in the 1960s.
The first term on the right-hand side is the Debye–Hückel term, with a constant, A, and the ionic strength I. β is an interaction coefficient and b the molality of the electrolyte. As the concentration decreases so the second term becomes less important until, at very low concentrations, the Debye-Hückel equation gives a satisfactory ...