Resolution in chromatographic separations can be compromised by nonuniform flow distribution, heterogeneous packing, or flow instabilities such as viscous fingering. In this work, the displacement of solutes within a chromatographic column was monitored with an advanced magnetic-resonance technique, echo-planar spectroscopic imaging (EPSI). Unlike conventional magnetic-resonance imaging, this approach allows multiple solutes to be observed simultaneously, providing separate "chemical images" for each component. Qualitative chemical images were obtained in approximately I min with approximately 1 mm(3) spatial resolution. EPSI allowed us to examine the multicomponent viscous fingering problem for the first time. While many features of the instability are preserved solute retention appears to slow the growth of solvent fingers.