Chromatography Forum

In EP monographs often solvents/reagents R are indicated to be used . What is this R meaning (reagent grade maybe?) and what is the equivalence with the solvents/reagents mentioned in USP?
Thank you.

you keep the answer in your post..R means reagent grade of commerce (analytical, chromatographic, general etc. which depends on the purpose)..

same for USP..

Actually the "R" indicates that there's a specific description of the solvent/reagent in the reagents section of the EP. For example, for simple old-school chloride identification via wet-chemistry using silver nitrate, you'll just read something like "add 1 mL of silver nitrate solution R" in the monograph. No concentration, no recipe for the reagent. These information can be found in the reagent section. For some reagents that are used in different concentrations or solvents you may even see denotation like R1, R2, etc.