ANALYTE PRECONCENTRATION PROCEDURE BASED ON PARALLEL-CURRENT OPEN-TUBULAR LIQUID-CHROMATOGRAPHY

A preconcentration method based on the focusing of the analyte in the tail of the pulse of the retentive layer moving in open capillary was developed. This technique was verified by the preconcentration of aque ous solutions of phenol, 2,4-dinitroaniline, phenanthrene and fluorant hene as model analytes. The pulse of a cyclohexanol layer moved in a f used-silica capillary of diameter 0.2 mm. The effects of the cyclohexa nol volume injected and sample volume on the focusing performance were examined. An enrichment factor of up to 30 was achieved.