CALCULATION OF PK(A) VALUES AND ZONE LENGTHS OF ANIONS, IN CAPILLARY ISOTACHOPHORESIS BY THE CALIBRATION METHOD

A method, based on determination of tile mobility as a function of pH using the capillary isotachophoresisis proposed. The method allows cal culation of the thermodynamic ionization constants and the molar quant ities of unknown acids and amino acids. The method utilizes the fact t hat the apparent pK values calculated from the mobilities, pK(u), a nd from the charge, pK(z), are in linear relationship with the thermodyn amic va lues pK(a). The relationships are expressed as linear calibrat ion equations from pH 3.0 to 9.0 and evaluated for calculation of pK(a ) and the specific zone lengths. The corrections for the ionic strengt h, the shift of pH, and the influence of hydrogen ion, are included in the empirical constants of the calibration equation and the mobility of counter ion.