This system is coupled to a mass spectrometer instrument for simultaneous MS and NMR analysis (i.e. MS and NMR analysis of the  LC analyte fractions) resolved. This instrument is particularly useful for the identification and structural characterization of unknowns (e.g. natural products or metabolites that are not annotated in current NMR or MS databases of small molecules). During operation of the LC-SPE-NMR-MS, a tiny fraction of the liquid chromatography (LC) effluent (1-5%) is directed to the MS system that detects and identifies fractions of the LC flow that appear to contain interesting compounds; those are then captured on a fraction collection system using a movable array of solid phase extraction (SPE) cartridges.  The compounds trapped on the SPE cartridges are dried and eluted using NMR buffer into NMR sample tubes. NMR tubes in racks are moved to the automatic sample loading system (autosampler) of the NMR instrument, where a variety of 1D and 2D NMR experiments will be used for small molecule identification and structure determination.