Quantitative coupling of supercritical fluid extraction and high-performance liquid chromatography by means of a coated open-tubular interface

Supercritical fluid extraction was coupled on-line with reversed-phase high -performance liquid chromatography (HPLC). An open-tubular column with a 95 % methyl-5% phenyl stationary phase was utilized as an interface between th e two systems. This phase allowed for good analyte focusing onto the packed analytical column and exhibited low reactivity. Due to the non-polar natur e of this phase there was a low tendency for analytes. to be prematurely ri nsed off the interface by condensed modifier. Using this approach, it was p ossible to transfer the extracted analytes quantitatively to the HPLC colum n in the presence of as much as 10% (v/v) methanol. By placing a 10 in guar d column at the head of the interface, the same could be accomplished with ethanol as the modifier: allowing the extraction to be conducted entirely w ith non-toxic fluids. The method also allowed the use of very practical ext raction parameters in terms of amount extracted, extraction flow-rate, extr action vessel volume, and extraction time. (C) 2001 Elsevier Science B.V. A ll rights reserved.