Modern Methods of Extraction = Microwave Assisted Extraction 02 | Basics of Phytochemistry (Part 08)
Download "Solution Pharmacy" Mobile App to Get All Uploaded Notes, Model Question Papers, Answer Papers, Online Test and other GPAT Materials - https://play.google.com/store/apps/de...
Microwave Assisted Extraction
Microwaves are non-ionizing electromagnetic waves (frequency range of 300 MHz to 300 GHz) which are useful in the extraction of Phytoconstituent. The prefix micro in microwave indicates that microwaves are the wave with shorter wavelength compared to radio waves. Microwaves are made up of two oscillating perpendicular fields which are electric field and magnetic field.
Microwave Assisted Extraction involves the use of microwave energy to heat a solvent in contact with a sample, in order to remove the analytes from the sample matrix into the solvent.
Microwaves directly act on the material which is able to absorb a part of its electromagnetic energy and can transform it into heat. This conversion of electromagnetic energy into heat energy occurs by two mechanism
1. Ionic conduction
2. Dipole rotation
Principle of Microwave Assisted Extraction
Heat is generated directly within the solvent by ionic conduction of the polar solvent's dipole rotation and dissolved ions. Accordingly, substances with low polarity are not heated while exposed to microwaves.
Irrespective of any drying method used, plants still do contain some moisture (microscopic traces of moisture that serve as a target for microwave heating). When this moisture inside the plant material gets heated under the influence of microwaves get evaporated and creates great pressure on the cell wall from inside because of swelling of plant cells. This causes the rupturing of cell wall (electroporation effect) thus facilitates the leaching of phytoconstituents (leakage and release of intracellular components) from the cells into the surrounding solvent. Higher temperature attained in MAE increases dehydration of cellulose and reduces its mechanical strength and this in turn helps solvent to access easily to compounds inside the cell.
Factor affecting the efficiency of MAE
1. Solvent properties
2. Extraction time
3. Matrix characteristics
4. Microwave power
5. Temperature
Instrumentation
Microwave oven is usually consists of the following components:
Magnetron : For the generation of microwave energy.
Wave guide : For the propagation of microwave energy from the source to microwave cavity
Applicator : For placing the extraction vessel (reactor) containing sample to be extracted.
Circulator : For reflection and homogenization of radiation (allows the microwave to move only in the forward direction).
Advantages of Microwave assisted Extraction (MAE)
1. Rapid exhaustive extraction: The process is time saving as the extraction process can be completed from few seconds to few minutes (5-20 min).
2. MAE consumes less solvents (easy recycled). Uses only few milliliters of solvent
3. Improved extraction yield and enhanced efficiency.
4. Avoid the thermal degradation and oxidation.
5. Favorable for thermo labile phytocontituents
6. Better process accuracy and precision as provided by the automation of the instrument.
7. MAE is one of the simplest methods and most effective among the several existing techniques.
8. Further, the energy loss to the surrounding environment in MAE is very less as the heating occurs in a selective and targeted manner.
9. Heavy metals and pesticide residue which are present in minute traces can be extracted from a few milligram of plant sample.
Get in touch with the solution by just clicking the following links-
Facebook Group- / solutionpharamcy
Mobile App - https://play.google.com/store/apps/de...
New Channel (Pharmacy Dictionary) / @pharmacydictionary
E-Mail for official and other work - [email protected]
#solutionpharmacy #Pharmacologyclass #Pharmacognosyvideos #GPAT