Estimating Stream Broadening in Free-Flow Electrophoretic Systems Based on the Method-of-Moments Formulation.

The resolving power of free-flow electrophoretic assays is often limited by the broadening of analyte streams as they migrate through the separation chamber. While molecular diffusion and flow hydrodynamics inherently contribute to such dispersion, non-idealities such as Joule heating and unwanted pressure-driven cross-flows among others can also significantly modify these contributions. In this chapter, we describe a theoretical approach to estimating stream broadening in free-flow electrophoretic systems under steady-state conditions based on the method-of-moments formulation. This methodology allows the determination of the spatial moments of solute concentration, thereby yielding measures for the mean position and spatial variance of the analyte stream.