Electrodialytic membrane eluent generators and suppressors for ion chromatography

Abstract

In 1975 Small, Stevens and Bauman published a scientific paper entitled "Novel Ion Exchange Chromatographic Method Using Conductimetric Detection."^ The use of ion exchange resins to separate a variety of ions, both positive and negative, had been in use for years on a preparative scale in the separation of metals, particularly the transition metals, lanthanides and actinides, some of which were considered extremely important for "strategic" reasons related to national defense and on an analytical scale for the determination of trace metals in geological samples.

What was new in this seminal work and what sparked the emergence of ion chromatography (IC) as a viable analytical technique was the realization of sensitive and virtually universal conductometric detection. The existing problem with conductometric detection at that time was that the conductivity of the eluting species of interest was "swamped out" by that of the much more abundant eluent electrolyte. This situation was likened to looking for a needle in a haystack. The problem was solved by using a combination of resins which stripped out or neutralized the ions of the eluent electrolyte leaving only the species of interest as the major conducting species in the eluent.