, Volume 81, Issue 5, pp 823–827 | Cite as

Determining the Chemical-Heterogeneity-Corrected Molar Mass Averages and Distribution of Poly(styrene-co-t-butyl methacrylate) Using SEC/MALS/UV/DRI

  • André M. Striegel
  • Imad A. Haidar Ahmad
Short Communication


Chemical heterogeneity, defined as the change (or lack thereof) across the molar mass distribution (MMD) in the monomeric ratio of a copolymer, can influence processing and end-use properties such as solubility, gas permeation, conductivity, and the energy of interfacial fracture. Given that each parent homopolymer of the copolymer monomeric components has a different specific refractive index increment (∂n/∂c) from the other component, chemical heterogeneity translates into ∂n/∂c heterogeneity. The latter, in turn, affects the accuracy of the molar mass (M) averages and distributions of the copolymers in question. Here, employing size-exclusion chromatography coupled on-line to multi-angle static light scattering, ultraviolet absorption spectroscopy, and differential refractometry detection, the chemical heterogeneity (given as mass percent styrene) was determined for a poly(styrene-co-t-butyl methacrylate) copolymer. Also determined were the chemical-heterogeneity-corrected M averages and MMD of the copolymer. In the present case, the error in molar mass incurred by ignoring the effects of chemical heterogeneity in the M calculations is seen to reach as high as 53,000 g mol−1 at the high end of the MMD. This error could be much higher, however, in copolymers with higher M or with larger difference among component ∂n/∂c values, as compared to the current analyte.


Chemical heterogeneity Copolymer Multi-detector size-exclusion chromatography Specific refractive index increment Molar mass Poly(styrene-co-t-butyl methacrylate) 


Compliance with Ethical Standards

Conflict of interest

The authors have no potential conflicts of interest to declare. The research presented here did not involve human participants and/or animals.


  1. 1.
    Lessard B, Graffe A, Marić M (2007) Macromolecules 40:9284–9292CrossRefGoogle Scholar
  2. 2.
    Lessard B, Tervo C, De Wahl S, Clerveaux FJ, Tang KK, Yasmine S, Andjelić S, D’Alessandro A, Marić M (2010) Macromolecules 43:868–878CrossRefGoogle Scholar
  3. 3.
    Haidar Ahmad IA, Striegel DA, Striegel AM (2011) Polymer 52:1268–1277CrossRefGoogle Scholar
  4. 4.
    Stiegel AM, Yau WW, Kirkland JJ, Bly DD (2009) Modern size-exclusion liquid chromatography, 2nd edn. Wiley, HobokenCrossRefGoogle Scholar
  5. 5.
    Striegel AM (2017) In: Fanali S, Haddad PR, Poole CF, Riekkola M-L (eds) Liquid chromatography: fundamentals and instrumentation, 2nd edn. Elsevier, Amsterdam, pp 245–273CrossRefGoogle Scholar
  6. 6.
    Striegel AM (2008) Anal Bioanal Chem 390:303–305CrossRefGoogle Scholar
  7. 7.
    Striegel AM (2010) Anal Bioanal Chem 402:77–81CrossRefGoogle Scholar
  8. 8.
    Striegel AM, Brewer AK (2012) Annu Rev Anal Chem 5:15–34CrossRefGoogle Scholar
  9. 9.
    Podzimek S (2011) Light scattering, size exclusion chromatography and asymmetric flow field flow fractionation. Wiley, HobokenCrossRefGoogle Scholar
  10. 10.
    Pitkänen L, Striegel AM (2014) Analyst 139:5843–5851CrossRefGoogle Scholar
  11. 11.
    Pitkänen L, Striegel AM (2015) J Chromatogr A 1380:146–155CrossRefGoogle Scholar
  12. 12.
    Grubisic Z, Rempp P, Benoit H (1967) J Polym Sci Polym Lett 5:753–759CrossRefGoogle Scholar
  13. 13.
    Beginn U (2008) Colloid Polym Sci 286:1465–1474CrossRefGoogle Scholar
  14. 14.
    Striegel AM (2017) Chromatographia 80:989–996CrossRefGoogle Scholar
  15. 15.
    Wyatt PJ (1993) Anal Chim Acata 272:1–40CrossRefGoogle Scholar
  16. 16.
    Striegel AM (2005) Anal Chem 77(5):104A–113ACrossRefGoogle Scholar
  17. 17.
    Haidar Ahmad IA, Striegel AM (2010) Anal Bioanal Chem 396:1589–1598CrossRefGoogle Scholar
  18. 18.
    Rowland SM, Striegel AM (2012) Anal Chem 84:4812–4820CrossRefGoogle Scholar
  19. 19.
    Hiller W, Hehn M (2014) Anal Chem 86:10900–10908CrossRefGoogle Scholar
  20. 20.
    Trainoff S (2008) US Patent 7386427Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature(outside the USA) 2018

Authors and Affiliations

  1. 1.Chemical Sciences DivisionNational Institute of Standards and Technology (NIST)GaithersburgUSA
  2. 2.Process Research and DevelopmentMerck and Co., Inc.RahwayUSA

Personalised recommendations