A Simple Question:
What is the definition of an ion-pairing reagent. Is an ion-pairing reagent defined as a chemical interaction with an analyte (e.g. TFA donates a proton to an analyte to facilitate ionization in LC/MS) or is it a chemical interaction with the stationary phase to protect active sites from distorting the peak shape and separation?
Thank you in advance for any insight

A simply answer. The stationary phase.

Adapted from Snyder et al. (1997) Practical HPLC Method Development:

The ion pairing reagent is attracted to the surface of the stationary phase because of its hydrophobic alkyl group, and the charge thereby attaches to the stationary phase. The negative charge on the phase is balanced by the positive ions from the reagent / buffer, thus allowing the exchange of positively charged samples with the stationary phase, and thus retention. This is similar to the ion exchange process.

Thank the gods for that.