Rapid reaction techniques optical monitors

The single-turnover reaction of MMOH ed with O2 has been monitored by time-resolved spectroscopic techniques. Stopped-flow optical spectroscopic and rapid freeze-quench (RFQ)... 

Kinetic data have been obtained with two methods (1) rapid mixing [86R2] and (2) temperature-jump [86T1]. Rapid mixing was used for studies on renaturation of polynucleotides. In these studies, complementary strands are mixed quickly, usually by a stopped flow technique, and the subsequent reaction is monitored by optical absorption. Temperature-jump was used for studies on oligomers and naturally occurring RNA sequences. In these studies, the temperature of an equilibrium solution is raised quickly, and the relaxation of the solution to the new equilibrium condition is followed by optical absorption or fluorescence. 

Third-order nonlinear optical experiments make it, in principle, possible to study ground-state proton transfer reactions. In particular, a technique called pump-dump—probe [34], where the first pulse is used to excite the system, the second to bring population back to the ground state, and a third pulse to monitor the absorption of the ground state, which at least briefly after the pulse should still be in the tautomeric form T (Figure 9.4) would make it possible to monitor ground-state populations upon rapid creation of the ground-state tautomer. So far this technique has not been used on simple tautomeric compounds. It has been used in some photoactive proteins where proton transfer steps after excitation are important [34]... 

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