What is main purpose of herbs lab
To extract bioactive compounds from herbs or spices using solid liquid extraction and analyze their purity and identity, using TLC and IR
What is solid liquid extraction?
A technique where a solvent (liquid) dissolves desired compounds from a solid material (herb/spice)
Why do we use reflex during extraction?
Keeps the solvent at constant high temperature without loss, allowing efficient extraction
What is the role of the heating mantle?
Provides controlled heat for their round bottom flask to maintain reflux
Why are boiling stones used during reflux?
Prevents, bumping and ensures smooth boiling
Why is acetone chosen as the extraction solvent?
It’s a good polar solvent that can dissolve essential oils and bioactive compounds effectively
How do you isolate the extract after reflux?
Cool the solution
Gravity filter to remove plant solids
Evaporate the solvent under a reduced pressure to obtain crude extract
Why use reduced pressure evaporation instead of open heating
It removes solvent safely at lower temperatures prevent preventing decomposition of heat, sensitive compounds
How do you calculate percentage recovery?
mass of extract/mass of original sample x 100%
How is the purity of the extract determined?
TLC: compare extract to standards
IR: confirms functional groups
Why might fenchone be difficult to see on TLC?
It lacks strong, UV active groups and may not react strongly with TLC stains
How do TLC and IR complement each other?
TLC shows relative purity and RF comparison to standards
IR: confirms functional groups, confirming identity of compound
What is the role of the waterless condenser?
Reflexes the solvent without using water, reducing environmental impact
How do you calculate water saved using a waterless condenser
Measure water, flow rate from irregular condenser for one minute and multiply the duration of waterless condenser use
Why is green chemistry relevant in this experiment?
Minimize hazardous solvent, use energy use, and water waste promoting safer and sustainable practises
What general steps are followed in the extraction experiment
Reflex herb/spice in acetone (solid liquid extraction)
Gravity filter to remove solids
Evaporate solvent under reduced pressure
Weigh extract and calculate recovery
Assess purity via TLC and IR
