BUFFER SYSTEMS AND PH GRADIENT SIMULATION

A computational method is described for calculating the pH gradient, with accompanying buffering power and ionic strength, of a mixture of different monoprotic buffers (with pKs distributed in the pH 3.5-9.5 interval) titrated within any pH span, from 1.5 up to 6.0 pH unit intervals. An optimization algorithm allows the linearization of the desired pH gradient to a maximum deviation from linearity of 1% of the created pH interval. At present, the optimization can be performed within reasonable time limits with a mixture of up to 10 different buffers. The program is interactive and allows intervention from the operator at any time. The method has found wide application for predicting and optimizing any pH gradient for electrophoretic fractionation of proteins by isoelectric focusing in polyacrylamide matrices, but in principle it can be applied to chromatographic processes involving elution driven by a pH gradient.