The use of turbulent flow chromatography and the isocratic focusing effect to achieve on-line cleanup and concentration of neat biological samples for low-level metabolite analysis.

The use of turbulent flow chromatography in conjunction with column switching isocratic focusing was used to perform on-line sample cleanup and concentration of neat rat plasma for the identification of low-level metabolites. The concentration was achieved by focusing multiple injections, which were cleaned by a turbulent flow column, onto an analytical column prior to elution into the mass spectrometer. In addition, the first application of turbulent flow chromatography for on-line sample cleanup of neat bile samples is reported. The on-line cleanup and concentration method extracts and concentrates a sample 20-fold in 1 h, and is completely automated.