Large sample volumes in preparative chromatography

Abstract

Equations are developed which relate output profiles resulting from large sample input volumes to the well-known expressions for elution chromatography. The sample volumes are such that output profiles are intermediate to the usual Gaussian curves resulting from very small sample volumes, and frontal output curves described by an integral Gaussian equation. Simple expressions which described the curve height at the maximum and curve width as a function of input volume are presented. This information is used to relate the apparent plate height to the plate height for small sample volumes and variation in observed resolution ( R′ s ) as a function of sample volume. It is demonstrated that 1/ R′ s = (1/ R s ) + ( v/Δ V R ). The equations are tested by reversed-phase high-performance liquid chromatography and preparative chromatography with silica as a stationary phase.