Procesos físicos en sistemas biomoleculares : cinética del crecimiento de monocristales de sacarosa para determinación estructural.

Abstract

In this work, the correlation between the growth kinetics of sucrose crystals and their quality, defined based on lattice parameters and the degree of crystal mosaicity, has been studied. For this purpose, sucrose solutions with initial concentrations close to 60%, 65%, 70%, and 75% were prepared, along with two growth temperatures for the crystals: 40°C and 60°C. Using polarized light microscopy, growth kinetics results were obtained for eight sucrose solutions, ranging from 7.83 µm/min to 69.26 µm/min, with a peak at an initial concentration of 65.54% and a growth temperature of 60°C. Subsequently, eight crystals were grown within a temperature-controlled muffle furnace under the aforementioned initial concentration-temperature conditions. Three out of the eight crystals, subjected to X-ray diffraction, successfully resolved the Monoclinic Type P crystal structure of sucrose. Among them, the crystal produced at 40°C with an initial concentration of 75.5 % was the closest to the values reported in the literature. This study demonstrated that sucrose solutions with abrupt concentration changes generate mosaic and unsuitable crystals for diffraction. Finally, correlations from -0.1227 and 0.3050 were found between growth kinetics, crystal mosaicity, and the relative error in the unit cell volume representing lattice parameters. This implies that there is very low correlation between crystal growth kinetics and their quality as defined in this study.