There’s Plenty of Gloom at the Bottom: The Many Challenges of Accurate Quantitation in Size-Based Oligomeric Separations

Published

July 26, 2013

Author(s)

Andre M. Striegel

Abstract

There is a variety of small-molecule species (e.g., tackifiers, plasticizers, oligosaccharides) the size-based characterization of which is of considerable scientific and industrial importance. Likewise, quantitation of the amount of oligomers in a polymer sample is crucial for the import and export of substances into the United States and European Union. While the characterization of ultra-high molar mass macromolecules by size-based separation techniques is generally considered a challenge, it is this author’s contention that a greater challenge is encountered when trying to perform, for quantitation purposes, separations in and of the oligomeric region. The latter thesis is expounded herein, by detailing the various obstacles encountered en route to accurate, quantitative oligomeric separations by size-exclusion chromatography, hydrodynamic chromatography, and field-flow fractionation. These include, among others, the diminished sensitivity of static light scattering (SLS) detection at low molar masses, the non-constancy of the response of SLS and of commonly-employed concentration-sensitive detectors across the oligomeric region, and the loss of oligomers through the accumulation wall membrane in asymmetric flow field-flow fractionation. The battle is not lost, however as, with some care and given a sufficient supply of sample, the quantitation of both individual oligomeric species and of the total oligomeric region is often possible.

Citation

Analytical and Bioanalytical Chemistry

Pub Type

Journals

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DOI Link

Keywords

Oligomeric separations, challenges, size-exclusion chromatography, hydrodynamic chromatography, field-flow fractionation, pre-manufacture notification.

Citation

Striegel, A. (2013), There’s Plenty of Gloom at the Bottom: The Many Challenges of Accurate Quantitation in Size-Based Oligomeric Separations, Analytical and Bioanalytical Chemistry, [online], https://doi.org/10.1007/s00216-013-7198-1 (Accessed September 20, 2024)