Howard G. Barth | Authors

This exploration into commercially available light scattering detection systems for size-exclusion chromatography (SEC) emphasizes new technologies and will help users understand the options.

Light scattering detectors are ideally suited for size-exclusion chromatography (SEC) because they provide the molecular weight and radius of gyration information of polymeric samples without column calibration. In this article, the fundamentals of light scattering as applied to SEC are introduced, with emphasis on the origin of the Rayleigh equation. This tutorial is geared to those new to the field or who already utilize light scattering and seek clarification regarding the multitude of equations associated with light scattering. Part X of this series will present a brief summary of commercially available light scattering instrumentation with emphasis on new detector technology. Owing to the complexity of data analysis and the many equations involved with light scattering measurements, part X will also include a glossary of principal symbols and a summary of relevant equations.

The effectiveness of a separation can be quantified by measuring the resolution. This article explains the factors influencing resolution and the equation for predicting the required number of theoretical plates to obtain a given esolution.

With these equations, you can predict how solute dilution will affect sensitivity.

How well do Gaussian-shaped profiles represent injected solute peaks after they are eluted through a chromatographic column? This question is explored along with a discussion of moment analysis for determining retention time, variance, and shapes of peaks.

The number of theoretical plates forms the basis of chromatographic theory, and is a key parameter used in all modes of chromatography for measuring column efficiency. Fortunately, it’s easy to measure.