Interactions of binary liquid mixtures with polysaccharides studied using multi-dimensional NMR relaxation time measurements
✍ Scribed by J. Kolz; Y. Yarovoy; J. Mitchell; M.L. Johns; L.F. Gladden
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 673 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
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✦ Synopsis
Nuclear magnetic resonance transverse T 2 relaxation time has proven to be a valuable parameter for characterizing liquid/polymer interactions. This measurement is applicable to many food, personal care, and cosmetic products that contain multi-component liquid mixtures. Here, we investigate the interactions of corn starch with water/glycerol mixtures of different weight compositions and explore liquid exchange dynamics; such a system is relevant to the personal care industry. We use a combination of chemical shift resolved 1 H T 2 relaxation measurements and corresponding two-dimensional T 2 relaxation exchange experiments using both a conventional experimental protocol and a modified method with the addition of NMR chemical shift selectivity. Two relaxation regimes were evident for the hydroxyl 1 H (found in both water and glycerol) whilst three relaxation regimes are evident for the aliphatic glycerol 1 H associated here with strongly bound, weakly bound, and free (bulk) liquid, respectively. At higher water contents preferential absorption of glycerol was evident. T 2 eT 2 exchange maps with a range of storage times reveal molecular exchange rates between all three regimes due to self-diffusion. Rapid exchange of water between the bulk and bound locations was evident in the case of pure water. Exchange rates for hydroxyl 1 H was considerably reduced by the inclusion of glycerol.