Synthetic polymers are essential components of advanced materials used in diverse technologies, including drug delivery systems, biocompatible materials, data storage, and electrochemistry. While liquid chromatography-mass spectrometry (LC-MS) offers valuable molecular-level information about polymer components, potentially revealing correlations between chemical structure, functionality, and molecular weight distribution, its application to polymer characterization faces a significant limitation: current MS-based approaches are largely restricted to relatively small oligomers (e.g., up to 5 kDa), which have limited applicability.
Our research aims to overcome this limitation by developing methods for the chemically selective reduction of high molecular weight polymers. This will produce oligomers that retain key information from the original polymer, such as the sequence distribution of copolymers. Furthermore, to address the complex challenge of analyzing chemical distributions in synthetic polymers, we will explore advanced separation techniques, including one-dimensional and two-dimensional liquid chromatography (1D and 2DLC). These methods will facilitate the characterization of properties such as end-group distributions and chemical compositions. Finally, robust data interpretation strategies, coupled with comparisons to established techniques like NMR, will be crucial for validating and interpreting the data obtained.
Fast determination of functionality-type × molecular-weight distribution of propoxylates with varying numbers of hydroxyl end-groups using gradient–normal-phase liquid chromatography × ultra-high pressure size-exclusion chromatography,G. Groeneveld, R. Salome, M.N. Dunkle, M. Bashir, A.F.G. Gargano, M. Pursch, E.P.C. Mes, P.J. Schoenmakers J. Chromatogr A 1659 (2021) 462644. https://doi.org/10.1016/j.chroma.2021.462644
In this paper, comprehensive two-dimensional liquid chromatography was used to determine the combined functionality-type and molecular-weight distributions of hydroxy‑functionalized propoxylates. Propoxylates derived from different initiators (one up to eight terminal hydroxyl groups) were separated in the first dimension using a gradient normal-phase LC separation (NPLC). In the second dimension ultra-high pressure size-exclusion chromatography separation (UHPSEC), further speciating distributions based on molecular size. The developed NPLC × SEC method with evaporative light-scattering detection can be used for the fast screening (< 30 min) of mutually dependent functionality-type and molecular-weight distributions of unknown propoxylates.
Selective Hydrolysis by Engineered Cutinases: Characterization of aliphatic-aromatic polyester homo and co-polymers by LC and LC-MS methods. Eman Abdelraheem ,Vasilis Tseliou ,Jessica Desport ,Martin Schürmann ,Paul Buijsen ,Ron Peters ,Andrea Gargano ,Francesco Mutti https://chemrxiv.org/engage/chemrxiv/article-details/654116a5c573f893f1838499
Here we describe the development and application of enzymes to the selective depolymerization of polyester co-polymers.
The performance, biodegradability, and recyclability of polymers can be tuned during synthesis by adopting monomers with different chemical characteristics. Recent research has shown the aptness of some hydrolases to depolymerize polyesters under mild conditions compared to chemical approaches. Herein, we engineered a cutinase from Thermobifida cellulosilytica (Tc_Cut2NVWCCG) for improved thermostability (up to 91 °C) and compared it with previously reported leaf-branch compost cutinase (LCCWCCG) for the hydrolysis of oligomers, aliphatic and aromatic polyester homopolymers, and a co-polyester. For both enzymes, higher hydrolysis rates were observed for aliphatic compared to aromatic homopolyesters. SEC-MS analysis revealed that the hydrolysis of aliphatic/aromatic co-polyesters occurred at the aliphatic monomers, significantly reducing the molecular weight and changing the end-group composition. These results underline the importance of co-polymer composition in the biodegradation of co-polymer systems and highlight the potential use of enzymes for the analytical characterization of synthetic polymers by selectively reducing their molecular weight.
Functionality-type and chemical-composition separation of poly(lactide-co-glycolide) using gradient elution normal-phase liquid chromatography with basic and acidic additives, M. Serizawa, J. Reekers, P. van Delft, M. van Bruijnsvoort, P.J. Schoenmakers, A.F.G. Gargano, J Chromatogr A 1730 (2024) 465137. https://doi.org/10.1016/J.CHROMA.2024.465137
PLGA is an important material in drug delivery systems. It is used in nanoparticle-containing drugs to prevent a sudden increase in drug concentration in the body when the drug is ingested. The LA/GA ratio and differences in the terminal structure of PLGA have a significant effect on the degradation rate of PLGA in the body.
To distinguish these distinctions, we created a unique ternary gradient liquid chromatography method utilizing base and acid additives. Initially, we used a gradient of hexane, a poor solvent, and ethyl acetate, a good solvent, with a mobile phase containing a base additive to separate non-ester-terminated PLGAs (ester-terminated PLGA and cyclic PLGA) based on their chemical composition. Subsequently, by switching the mobile phase to THF containing an acid additive, we were able to elute acid-terminated PLGA.
This method offers the advantage of quick analysis compared to traditional NMR methods, making it potentially valuable for future industrial research. Furthermore, it can be applied to high molecular weight PLGA of 180 kDa, making it useful for the development of high molecular weight PLGA, which is challenging to analyze using mass spectrometry techniques such as MALDI-TOF-MS.
CAST scientist Luca Tutiš together with Govert Somsen and Andrea Gargano as well as AstraZeneca, Novartis and GSK have just published a manuscript describing a novel LC-MS method for impurity profiling of therapeutic phosphorothioated oligonucleotides.
CAST scientists Annika van der Zon and Ziran Zhai have just published two manuscriptsshowcasing significant advances in the low flow analysis of intact antibodies and
Scientists from the CAST team and related projects within the Center of Analytical Science Amsterdam actively participated with lectures, posters and social contributions to the HPLC2025 conference in Brugge, Belgium.
