 Regardless, these techniques have still seen use, such as in the investigation of the Heck reaction where the heterogeneous nature of the reaction precluded utilization of the techniques described above.and SOMO-activation by organocatalysts Despite their shortcomings, these techniques may serve as excellent calibration methods.Reaction progress data may often most simply be presented as plot of substrate concentration ([A]"t") vs. time ("t") or fraction conversion ("F") vs. time ("t").