Feasibility of supercritical fluid extraction with on-line coupling of reversed-phase liquid chromatography for quantitative analysis of polymer additives

An on-line analytical method for determining polymer additives which incorporates (a) sample preparation and concentration, (b) chromatographic separation, and (c) UV detection is presented. The on-line system which combines supercritical fluid extraction (SFE) and high-performance liquid chromatography (LC) allows analytes to first be extracted and transferred to the SFE sorbent trap, then desorbed from the trap and presented to the LC system. No UV detector interference from residual dissolved CO2 in the mobile phase was observed since CO2 is eliminated by a pre-wash of the sorbent trap with a small amount of water. Reversed-phase LC with a mobile phase gradient of acetonitrile–water was employed. The described method allows a complete analysis to be processed in less than 30 min.