Extraction using magnetic stirring (control experiment):
80.0 grams of sample was taken and 1.0 litere distilled water
was added in a glass beaker in order to keep the plant materials
along with ultrasound tip fully immerse in solvent. The beaker
was covered using aluminum foil to prevent loss of solvent by
evaporation. This beaker was stirred magnetically for 3 hours.
In order to have the fair comparison with ultrasound system,
where ultrasonic bath temperature is around 45 °C without
external heating, the temperature of the extraction bath for
control process was also maintained at 45 °C. This would also
provide idea about improvements with ultrasound extraction
other than temperature induced effects of ultrasound. Extract
samples were taken at every 30 minutes and the optical density
was determined with the help of UV-VIS spectrometer. At the
end of 3 hours, the yield and extraction efficiency of each
sample was determined by gravimetric method. The extract was
tightly closed and stored at low temperature for future reference.