March 29th 2024
This installment of Tips & Tricks deals with pressure monitoring for GPC/SEC systems and gives hints for efficient troubleshooting to solve issues that are identified in the laboratory.
Quantitative Metrics to Properly Describe Solute Elution in Size-Exclusion Chromatography
February 16th 2024The purpose of this short tutorial article is to review the terms and official nomenclatures for size-exclusion separations and to provide some guidance and recommendations for practicing chromatographers. The interconversion between the different metrics is explained and some examples are presented.
Calibrating the Low Molar Mass Range in GPC/SEC Using Oligomer Peaks
February 15th 2024Reliable calibration curves in the low molar mass region can be obtained when using the elution volumes of all separated oligomers of low molar mass standards on high resolution columns. This article explains how to do this.
New Strategies for Oligonucleotide Aggregate Analysis
January 15th 2024Technological limitations have made it difficult for scientists to identify oligonucleotide aggregates. This can pose challenges when finding techniques to reliably analyze size variants for large nucleic acids and lipid nanoparticles (LNPs).
The LCGC Blog: Polymers, Macromolecules, and Nanomaterials in the Separation Science Curriculum
August 2nd 2021In 2015, the American Chemical Society’s Committee on Professional Training added a requirement to the ACS degree certification program that undergraduates learn about macromolecules, supramolecular aggregates, and nanomaterials (MSN). This requirement can be met by a specialized course in these topics, but many programs are also choosing the distribute these topics across the curriculum.
Molar Mass Determination of Collagen Peptides
April 1st 2021Hydrolyzed 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.
The Benefits of Multi‐angle Light Scattering for Size‐Exclusion Chromatography
March 1st 2021Analytical 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.
Chromatography Fundamentals, Part IX: Light Scattering Detectors for Size-Exclusion Chromatography
October 1st 2020Light 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.