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Sophia Kenrick, PhD,* is an application scientist at Wyatt Technology Corporation, 6300 Hollister Ave, Santa Barbara, CA 93117-3253.

Articles

Quantifying AAV Quality Attributes Using SEC–MALS

This instalment describes the interplay between column length, pore size distribution, and particle size to optimize GPC/SEC separations.

Tips & Tricks GPC/SEC: Separation Range and Resolution

Hydrolyzed collagens (collagen peptides) are water-soluble products obtained by hydrolysis of natural proteins and used for dietary supplements. A simple GPC/SEC method is described for molar mass determination of collagen peptides, allowing reliable molar mass determination using ultraviolet (UV) detection.

Molar Mass Determination of Collagen Peptides

Analytical size-exclusion chromatography (SEC) often suffers from several limitations. This article shows how some of these limitations can be partly (or even completely) resolved by a multi-angle light scattering (MALS) detector for the determination of molar mass distributions of synthetic and natural polymers.

The Benefits of Multi‐angle Light Scattering for Size‐Exclusion Chromatography

How to create a calibration curve when no chemically-matching reference materials with narrow molar mass distribution are available.

Tips & Tricks GPC/SEC:  Cumulative Distributions and Cumulative Match Calibration

A review of alternative approaches to narrow standard calibration.

Tips & Tricks GPC/SEC: Alternatives to Narrow Standard Calibration in GPC/SEC

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.

Chromatography Fundamentals, Part IX: Light Scattering Detectors for Size-Exclusion Chromatography

Daniel Some, PhD, is director of marketing and principal scientist, at Wyatt Technology Corporation, 6300 Hollister Ave, Santa Barbara, CA 93117-3253.

The macroscopic properties of material based on poly(D,L-lactic-co-glycolic acid) (PLGA) polymers are tunable by molar mass distribution and degree of branching, enabling optimization for applications in the pharmaceutical and medical industries. Size-exclusion chromatography followed by online multi-angle light scattering with intrinsic viscosity detection (SEC–MALS–IV) is an advanced analytical method for determining absolute molar mass distributions, identifying polymer conformation and quantifying branching. SEC–MALS–IV overcomes the errors that can be encountered in molar mass determined by conventional SEC, which arise from chemical composition and molecular structure, and provides comprehensive characterization of PLGA to facilitate the targeted development of optimized polymer.

Molecular Structure of Poly(Lactic-co-Glycolic acid) by SEC with Advanced Detection

Water-soluble macromolecules require water as a mobile phase, and method development therefore seems to be straightforward. At second glance, however, aqueous gel permeation chromatography/size-exclusion chromatography (GPC/SEC) is complex and the choice of the stationary phase and pH are crucial. In addition, mobile phase additives are often required to allow for interaction-free separations.

Tips & Tricks GPC/SEC  Aqueous GPC/SEC for Water-Soluble Macromolecules

The chemistry of samples analyzed using gel permeation chromatography/size-exclusion chromatography/gel filtration chromatography (GPC/SEC/GFC) is very diverse. Different chemistries of stationary phases are required to allow for true size separation. Several types of materials are available, all of which have their advantages and limitations. While silica‑based stationary phases are most common in high performance liquid chromatography (HPLC), for macromolecules polymer-based phases are popular.

Size-Exclusion Chromatography (SEC) | Topics