The Postnova Characterization Platform - Characterization of Polymers, Proteins and Particles by FFF and SEC with Advanced Detection

Importance of the Topic

Polymers, proteins and particulate materials are central to fields such as pharmaceuticals, nanotechnology and materials science. Combining fractionation techniques with advanced detectors provides detailed insights into molecular weight, size distribution, chemical composition and structural conformation. This comprehensive characterization informs formulation development, quality control and regulatory compliance.

Objectives and Overview of the Study

This work introduces a modular platform that integrates Field Flow Fractionation (FFF) and Size Exclusion Chromatography (SEC) with multiple detectors for the analysis of polymers, proteins and particles. The goals are:

• To demonstrate complementarity of FFF and SEC in separating species across a broad size range
• To showcase applications using asymmetric flow FFF (AF4), centrifugal FFF (CF3) and thermal FFF (TF3)
• To illustrate the benefit of coupling fractionation with detectors such as multi-angle light scattering (MALS), refractive index (RI), UV, viscometry, ICP-MS and dynamic light scattering (DLS)

Methodology and Instrumentation

Separation modules include:

• AF2000 flow FFF: cross-flow separation based on hydrodynamic size
• CF2000 centrifugal FFF: density and size separation using centrifugal fields up to 2500 g
• TF2000 thermal FFF: separation via thermal diffusion in temperature gradients
• SC2000 SEC: size exclusion in standard columns for soluble polymers

Detection modules employ:

• RI, UV/vis (DAD), fluorescence and evaporative light scattering detectors for concentration and composition
• Viscometer for intrinsic viscosity and conformational data
• MALS for absolute molecular weight and radius of gyration
• DLS for hydrodynamic radius
• ICP-MS for elemental analysis after FFF separation

Main Results and Discussion

• SEC vs. AF4: AF4 resolved high-molecular weight and particulate samples that challenge standard SEC, such as crosslinked hyaluronic acid and emulsions
• PLGA nanoparticles: Mark-Houwink analysis distinguished linear and branched species
• Hyaluronic acid: FFF preserved >80% recovery of crosslinked samples versus <10% for SEC, revealing degradation on sterilization
• Polymersomes: Combined MALS and DLS demonstrated mixed morphologies (spheres, tubes) consistent with TEM
• SiO2 and tattoo inks: AF4-ICP-MS enabled size-resolved elemental quantification of pigments and metal oxides
• CF3 applications: Centrifugal FFF coupled with DLS and ICP-MS separated gold and silver nanoparticles by density and provided chemical specificity in one run
• TF3 applications: Thermal FFF discriminated polystyrene and PMMA standards with identical hydrodynamic radii, revealing composition-dependent retention

Benefits and Practical Applications

• Enhanced resolution for complex macromolecular and particulate mixtures
• Non-destructive analysis preserving sample integrity
• Multi-detector data fusion enables comprehensive characterization in a single experiment
• Improved recovery and reduced sample preparation for high-molecular weight or crosslinked systems
• Scalable modularity allows tailoring to research, quality control and nanomaterial safety assessments

Future Trends and Applications

Anticipated developments include:

• Integration with microfluidic fractionation for high-throughput screening
• Advanced software for automated method development and data interpretation using machine learning
• Expanded pairing with spectroscopic and mass spectrometric detectors for structural elucidation
• Real-time monitoring of reaction kinetics in polymer synthesis and nanoparticle assembly
• Applications in single‐particle analysis for biologics and precision medicine

Conclusion

The Postnova platform unifies FFF and SEC with a suite of detectors, enabling detailed size, weight and compositional analysis across diverse sample types. This flexibility and data richness support deeper understanding of macromolecules and particles for research, industrial applications and regulatory compliance.

Reference

• Y. Kohl et al., Biopolymer Nanoparticles for Therapeutic Applications: Characterization and Assessment of Biocompatibility, Nanosafety Conference 2013
• S. Tadjiki and R. Klein, Mass Discrimination of Au and Ag Nanoparticles by Centrifugal FFF and ICP-MS, The Column, 2014, 10(14), 11–16