With their large distributions culminating in wide envelopes of – almost exclusively – co-eluting peaks, polymers certainly present a unique challenge relative to the analysis of small molecules. If anything, this challenge has spurred innovations which have also benefited other fields. A good example has been the work on polymer analysis with 2D-LC in the first years of this millennium, which have certainly contributed to recent developments on the technique [1,2].
In his review, Wouter Knol (Van ‘t Hoff Institute for Molecular Sciences) reviews another research area which offers a lot of room for innovations: detection. Together with the co-authors, Knol provided an exhaustive overview of applications of detection techniques in LC for polymer analysis. For each detection technique, notable recent applications are discussed and the authors distilled the key advantages and disadvantages of each approach.
One particularly useful trait of the review is this table which summarizes all key strengths and weaknesses of each detection technique employed for LC in polymer analysis. Reprinted with permission from [3].
Knol and co-workers noted that promising approaches receive surprising attention in recent literature. He concluded that the opportunities deserve more attention. You can download and read the paper, which was published open-access in the special Reviews 2021 issue of Journal of Separation Sciences, here.
Example of a separation of complex polyether polyols with LC×LC-MS by Groeneveld et al. showing a clear structure based on the number of ethylene oxide/propylene oxide units in the polymer. Reprinted with permission from [4].
References
[1] Recent Developments in Two-Dimensional Liquid Chromatography: Fundamental Improvements for Practical Applications
B.W.J. Pirok, D.R. Stoll and P.J. Schoenmakers, Anal. Chem., 2019, 91(1), 240-263, DOI: 10.1021/acs.analchem.8b04841
[2] Comprehensive Two-Dimensional Ultrahigh-Pressure Liquid Chromatography for Separations of Polymers E. Uliyanchenko, P.J.C.H. Cools, Sj. van der Wal and P. J. Schoenmakers, Anal. Chem. 2012, 84, 18, 7802–7809, DOI: 10.1021/ac3011582
[3] Detection challenges in quantitative polymer analysis by liquid chromatography, W.C. Knol, B.W.J. Pirok, and R.A.H. Peters, J. Sep. Sci. 2020, DOI: 10.1002/jssc.202000768
[4] Characterization of complex polyether polyols using comprehensive two-dimensional liquid chromatography hyphenated to high-resolution mass spectrometry G. Groeneveld, M.N. Dunkle, M. Rinken, A.F.G. Gargano, A. de Niet, M. Pursch, E.P.C. Mes, and P.J. Schoenmakers, J. Chromatogr. A, 1569, 2018, 128-138, DOI: 10.1016/j.chroma.2018.07.054
Wouter Knol was a PhD candidate in the group of Peter Schoenmakers and Bob Pirok. He worked in the UNMATCHED project in Amsterdam and mainly focuses on techniques to determine the sequence distribution of polymers.
You can read more about him on our Team page.
