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 aqueous solutions of phenol, 2,4-dinitroaniline, phenanthrene and fluoranthene as model analytes. The pulse of a cyclohexanol layer moved in a fused-silica capillary of diameter 0.2 mm. The effects of the cyclohexanol volume injected and sample volume on the focusing performance were examined. An enrichment factor of up to 30 was achieved.