pH jump: A relaxational approach Academic Article uri icon


  • Back-protonation of the 8-hydroxy-1,3,6-pyrenetrisulfonate anion (RO- + H+ → ROH (kb)) initiated by a laser pulse photolysis of the neutral molecule (the pH jump method, pHj) is used in order to establish the chemical equivalence between the generated protons and water equilibrium protons. The diffusion-controlled nature of the back-reaction is established by checking the temperature and isotope (H/D) dependence of the reaction. A relaxation kinetics analysis is carried out in order to follow the time evolution of [H+]. The same analysis is proved to be applicable for the description of the bleaching kinetics of an acid-base indicator (BCG) present in the solution at the time of the pH jump.

publication date

  • October 1, 1983