Experimental investigations on validity of moving chemical reaction boundary equation for the strong acid-weak base system with an excess of potassium chloride.

A moving chemical reaction boundary (MCRB) is formed by the weak alkali NH[sub 3]·H[sub 2]O and strong acid HCl with an excess of potassium chloride as background electrolyte. The experimental results are compared with the predictions in accordance with the moving chemical reaction boundary equation (MCRBE). If the MCRB is cathodic, the experimental results are in agreement with the predictions by the MCRBE. However, if the MCRB is anodic, the experimental results significantly deviate from the predictions of the MCRBE. A corrected MCRB equation is proposed for such conditions. The findings are evidently different from those in our early reports (J. Chromatogr. A, 891 (2000): 337-347; 907 (2001): 347-352; 922 (2001) 283-393). This study is of obvious benefit to capillary electrophoresis and isoelectric focusing. [ABSTRACT FROM AUTHOR]