Dissertação
Análise rápida da acidez de bebidas em microplacas de papel empregando entalpimetria no infravermelho
Fecha
2016-03-11Autor
Ferreira, Daniele de Freitas
Institución
Resumen
The paper devices are receiving high emphasis in chemical analysis due to the attractive
features as low cost, facility of use and fabrication, low consumption of reagents and
easy disposal, high surface area, portability and biodegradability. In this way, as an
alternative for acidity evaluation in beverages, this work proposes an unprecedented
combination of paper microplates and thermal infrared enthalpimetry (TIE), allowing a
rapid and effective analytical method for determination of acidity in beverages according
to the principles of green chemistry. Therefore, it was performed the determination of
total acidity in soft drink samples and total, fixed and volatile in red, white and sparkling
wine with comparison of results with conventional titration method. The proposed system
was performed by the use of a microplates paper fabricated by the wax printing method,
an infrared camera for temperature monitoring and a multichannel pipette for reagent
addition. Firstly, it was observed that the conditions of pipette as well as the temperature
measurement in data processing could directly influence the deviation of the results.
Compared to conventional titration method the TIE in paper platform presented
desirable results, with good agreement (from 96 to 104%) for all evaluated samples.
Moreover, it was observed that it provided a higher sample throughput that reached 480
samples h-1 for fixed acidity. A significant reduction in the sample and reagent
consumption was observed, with energy consumption up to 60 times lower in relation to
conventional method. Thus, the proposed system in this work presented a good
performance, and it could be considered a rapid, reliable and inexpensive to acidity
analysis in routine following the principles of green chemistry.