NEOS and NEOS GR
While the analysis step is complete after 15 to 30 minutes, extraction takes at least several hours. The extraction step of essential oils represents 70 percent of the total processing time.
Microwave extraction makes use of physical and chemical phenomena that are fundamentally different compared to those applied in conventional isolation techniques.
These novel processes can produce essential oil in concentrate form, free from any residual solvents, contaminants, or artifacts.
How NEOS works
The Milestone NEOS performs solvent-free microwave extraction at atmospheric pressure of essential oil in plant material.
The method involves placing the sample in the microwave reactor, without any added solvent or water. The internal heating of the water within the sample distends its cells and leads to rupture of the glands and oleiferous receptacles.
This process thus frees essential oil, which is evaporated by the in-situ water of the plant material.
A cooling system outside the microwave oven continuously condenses the vapours, which are collected in specific glassware.
The excess of water is refluxed back to the extraction vessel in order to restore the in-situ water to the sample. Once the essential oils have been extracted they can be analyzed directly by GC-MS without any preliminary clean-up or solvent exchange steps.
Example of typical applications
|Extraction time (min.)||10||180||60|
|Total oxygenated compounds (%)||1,6||0,9||1,1|
|Total non oxygenated compounds (%)||97,4||98,5||98,2|
|Time (min)||Yield (%)||Time (min)||Yield (%)|
|Basil (Ocimum Basilicum L.)||30||0,029||270||0,028|
|Garden mint (Mentha Crispa L.)||30||0,095||250||0,095|
|Thyme (Thymus Vulgaris L.)||30||0,160||250||0,161|
This green extraction is an original “upside down” microwave alembic combining microwave heating and earth gravity at atmospheric pressure.
It is important to note that this green method allows extracting essential oils without distillation and evaporation, which are the most energy consuming between the unit operations.
The distillation step, which can represent up to 80% of the total analytical procedure, is no longer required. Whereas traditional processes are carried out within 3 hours, solvent-free microwaves hydrodiffusion plus gravity requires no more than 30 minutes.
How NEOS GR works
Based on a relatively simple principle, the MHG technology (Microwave Hydrodiffusion and Gravity) involves placing plant material in a microwave reactor, without adding any solvent or water. The internal heating of the in-situ water within the plant material distends the plant cells and leads to the rupture of glands and oleiferous receptacles.
The physical phenomenon, known as hydrodiffusion, allows the extract (water and essential oil) diffused outside the plant material, to drop by earth gravity out of the microwave reactor and fall through a perforated Pyrex disc.
The NEOS-GR leaded to the grant of the European patent EP 1 955 749.
|Sample amount (gram)||500||500|
|Yield (%)||0,33 ± 0,09%||0,35 ± 0,07|
|Mentha spicata L.||Mentha pulegium L.|
|Extraction Time (min)||20||90||20||90|