This document introduces a superficially porous, silica-microsphere packing called Poroshell™, which has excellent kinetic properties and enables stable, high-resolution gradient chromatography of biomacromolecules such as proteins, polypeptides, nucleic acids, and DNA fragments at high speed. Poroshell™ packings can be used with conventional equipment without loss of performance. This technology is useful for rapidly monitoring preparative separations of genetically engineered macromolecules, process control monitoring of fermentation broths or cell-reaction systems, quantitation of polymerase chain reaction fragments, monitoring protein conjugation reactions, and similar applications where very fast, reproducible separations are required.