Communication. Reverse flow injection or reagent injection? Normal flow injection, reverse flow injection and single-boundary measurements

Abstract

The terms sample injection and reagent injection are inadequate in describing flow injection systems in which a monitorand that is not the determinand is produced on-line. The term reverse flow injection may not be self-evident, but terms such as normal flow injection and reverse flow injection can be used effectively to indicate whether a chemical species is in the injectate or the carrier stream, and whether a product is being formed by a concentration-limited species dispersing into or out of the bolus. Any term replacing the term reverse flow injection must be equally versatile. For flow analysis using a single boundary between two solutions there is a need for a term which indicates whether a chemical species, particularly if it is the determinand or a concentration-limited reagent forming a monitorand, is in the front or rear solution.