Polymorphic Effects at the Eutectic Melting in the H2O-Glycine System
Journal of Thermal Analysis and Calorimetry
, E-ISSN: 1572-8943
||DSC Eutectic melting Eutectic temperature Glycine Polymorphism Water
Boldyreva Elena V.
Novosibirsk State University, Ul. Pirogova 2,
630090 Novosibirsk, Russia
Institute of Geology and Mineralogy SB RAS,
Pr. Ac. Koptyuga 3, 630090 Novosibirsk, Russia
Nikolaev Institute of Inorganic Chemistry SB RAS,
Pr. Ac. Lavrentieva 3, 630090 Novosibirsk, Russia
Institute of Solid State Chemistry and Mechanochemistry,
SB RAS, ul. Kutateladze, 18, 630128 Novosibirsk, Russia
Solid mixtures of ice with three glycine polymorphs were heated up to the eutectic melting and the DSC has detected the eutectic temperatures of −2.8 °C for α-, −3.6 °C for β-, and −2.8 °C for γ-glycine. DSC peaks of the eutectic melting are rather strange in shape, indicating unclear processes in the solutions. Accurate DSC measurements of extremely small samples can probably provide us with the physicochemical tool for the investigation of polymorphic differences among different solutions. This may be important in relation to different bioavailability of solutions prepared from different polymorphs. Eutectic temperature of −4.7 °C in water–glycine system allows us to suggest that the unknown polymorph of glycine exists.