Resumen de Multiple Solid–Liquid Extraction: Determination of Extraction Yield through UV–Vis Spectroscopy
Elia Bergamin, Giacomo Fabris, Matteo Neffat, Paola Baron Toaldo, Daniela De Luchi, Renato Bonomi
A class of 18 students attending the last year of an Italian high school was divided into groups and performed the extraction of pigments contained in hibiscus tea. Each group worked at a different temperature and carried out multiple extractions using distilled water as a solvent. By means of UV–vis spectroscopy it was possible to determine the yield of each individual extraction and then to study the effect of temperature on the extraction itself. The method is easy to implement, it does not require the use of hazardous reagents or special safety precautions, and it is very cheap. The laboratory part was carried out in 3 h time, while the analysis and data processing took about 4 h. On an educational level, the students learned to process and analyze large amounts of data, and they became familiar with the UV–vis spectrophotometer and eventually had to solve the problems independently.
