Dual membrane annular helical suppressors in ion chromatography

A dual membrane annular helical configuration is shown to be a highly efficient low dispersion suppressor for ion chromatography. The device contains one filament-filled membrane tube inserted inside another closely fitting membrane tube of the same type. The dual membrane assembly is coiled as a small diameter helix, the shape being retained by the filament. The column effluent flows in the annular space between the two membranes; regenerant flows through two separate channels, inside the inner membrane and through a jacket which surrounds the entire device. Compared to simple filament-filled membrane helices, these devices exhibit a substantially larger available membrane surface area per unit dispersion of an injected band. 20 references, 3 tables, 2 figures.