Method for quantitative determination of spatial polymer distribution in alginate beads using Raman spectroscopy

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Matthias Heinemann - (First author)
  • Holger Meinberg - (Author)
  • Jochen Büchs - (Author)
  • Hans-Jürgen Koss - (Author)
  • Marion Bettina Ansorge-Schumacher - , RWTH Aachen University (Author)

Abstract

A new method based on Raman spectroscopy is presented for noninvasive, quantitative determination of the spatial polymer distribution in alginate beads of approximately 4 mm diameter. With the experimental setup, a two-dimensional image is created along a thin measuring line through the bead comprising one spatial and one spectral dimension. For quantitative analysis of the Raman spectra, the method of indirect hard modeling was applied to make use of the information contained in the entire recorded spectra. For quantification of the alginate signals from within the beads, a calibration curve acquired from sodium alginate solutions was used after it was shown that only negligible differences occur between signals from alginate solutions and alginate gels. The distribution of alginate over the bead gel matrix was acquired with high spatial (51 mm) and time (12 s) resolution. The inhomogeneous distribution obtained using the new measuring technique is qualitatively in excellent agreement with data from the literature. In contrast to known measuring techniques, correct quantitative information about the spatial polymer distribution within the matrix was derived. It gave an alginate mass fraction of approximately 0.045 g/g at the edges and 0.02 g/g in the center of the beads. Next to the determination of mere polymer concentrations, the excellent time resolution of the presented method will enable investigation of the dynamic process of gel formation and it will also serve as a basis for investigation of mass transfer of small diffusing molecules in alginate matrices.

Details

Original languageEnglish
Pages (from-to)280-285
JournalApplied spectroscopy : an international journal of spectroscopy
Volume2005
Issue number59
Publication statusPublished - 2005
Peer-reviewedYes
Externally publishedYes

External IDs

Scopus 16244412966
ORCID /0000-0002-2912-546X/work/171551995

Keywords

Keywords

  • Hydrogel, Alginat, Netzwerk, Biokatalyse