coupled (indicator) reaction

in analysis
Synonym: indicator reaction
https://doi.org/10.1351/goldbook.C01380
A reaction which follows the (slower) reaction of kinetic interest, so as to provide means of @MT06831@ the formation of a reaction product. This reaction is sometimes referred to as the indicator reaction.
Source:
PAC, 1993, 65, 2291. (Nomenclature of kinetic methods of analysis (IUPAC Recommendations 1993)) on page 2294 [Terms] [Paper]