Thermally-induced dielectric relaxation spectra in three aldohexose monosaccharides
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Three aldohexose monosaccharides, d-glucose, d-mannose, and d-galactose, were examined by scanning temperature dielectric analysis (DEA) from ambient temperatures through their melts. Phase transitions, including glass transition (T g) and melting temperature (T m), were evaluated by differential scanning calorimetry (DSC). The monosaccharides were found to exhibit thermally-induced dielectric loss spectra in their amorphous-solid phase before melting. Activation energies for electrical charging of each of the monosaccharides were calculated from an Arrhenius plot of the tan delta (e″/e′, dielectric loss factor/relative permittivity) peak frequency versus reciprocal temperature in Kelvin. The DEA profiles were also correlated with the DSC phase diagrams, showing the changes in electrical behavior associated with solid–solid and solid–liquid transitions.
KeywordsDEA Dielectric analysis DSC Differential scanning calorimetry Monosaccharides Activation energy Transition temperatures
This research was cited as the best undergraduate poster in competition at the North American Thermal Analysis Society, NATAS 2010 in Philadelphia PA. Thank you to all the organizers and participants of the conference who support undergraduate and graduate student researchers.
- 1.Morrison RT, Boyd RN. Organic chemistry. 2nd ed. Boston: Allyn and Bacon; 1966. p. 167–9.Google Scholar
- 6.Seo J, Oh J, Kim HK, Hwang Y, Yang YS, Kim SJ. Study of glass transition temperatures in sugar mixtures. J Korean Phys Soc. 2005;46(3):606–9.Google Scholar
- 8.Kaminski K, Kaminska E, Wlodarczyk P, Paluch M, Ziolo J, Ngai KL. Dielectric relaxation study of the dynamics of monosaccharides: d-ribose and 2-deoxy-d-ribose. J Phys Condens Matter. 2008;20:355104–12.Google Scholar