Contributions to the spectroscopic-kinetic analysis of linear reaction systems: Systems with two linearly independent reactions using the concept of parallel projection

Multistep protolysis or metal-complex systems can be divided into their individual titration equilibria by the concept of projective mapping using diagrams which contain only absorbance data. In this way, the individual equilibria constants and their ratios can be very easily determined. The concept can be transfered to the spectroscopic-kinetic analysis of linear reaction systems. Reaction systems which are described by two linearly independent concentration variables (5=2) can be reduced to systems which depend only on one linearly independent concentration variable (5=1) by replacing the perspective projection by a parallel projection. The new method is demonstrated by application to the spontaneous hydrolysis of Boc-gly-ONP (N-tert.-Butoxycarbonyl glycine p-nitrophenylester) and oNPA (o-nitrophenyl acetate) in borax buffer (pH = 8.7).