DESENVOLVIMENTO DE ACESSÓRIO PORTÁTIL DE CONTROLE DE TEMPERATURA PARA MEDIDAS ESPECTROSCÓPICAS

Abstract

Temperature is a natural phenomenon that may modify the structure of chemical compounds and hence their properties. We aimed to develop a simple portable system based on the Peltier principle for spectral characterization of compounds with temperature-dependent structure. The device was constructed and adapted to three pieces of equipment: X-ray diffractometer, vibrational spectrophotometer, and electronic spectrophotometer. The device was evaluated by using commercial thermochromatic inks, whose color depends on temperature. The X-ray diffraction results for the ink whose color changed at a transition temperature of 31 oC showed that the peak at 2θ = 21.6o decreased probably due to alterations in the structures of the components underlying the ink color and solvent. The absorption spectra showed reduced absorption, typical of change in color, a property that is inversely proportional to temperature. The device working range varied from 15 to 75 oC, and it was constructed from parts that are easily available in the national market at an affordable price. The device can be adapted to different equipment with distinct configurations regarding the sample compartment.