Vacuum concentrators use a combination of heat, vacuum and centrifugal force for the evaporation of volatile samples. The method is used for evaporation, drying, purification and especially fast concentration. It takes advantage of the fact at pressures of a few hectopascal, volatile substances boil at room temperature without freezing the specimen.
The additional centrifugal force from rotation prevents bumping and changes the liquid level in the test tubes, thereby increasing the evaporation surface. The applied heat increases the rate of evaporation without causing overheating of the specimens under vacuum. Rotational Vacuum Concentrators (RVC) are an alternative to the following methods:
- Distillation systems and rotary evaporators use high temperature for evaporation and operate at nearly atmospheric pressure or vacuum levels down to approximately 100mbar.
- Freeze drying systems operate at very low temperatures and high vacuum down to less than 0.01 mbar. Although sublimation preserves the specimens, it is time consuming, and not all solvents are suitable for freeze drying.
Rotational vacuum concentration occupies a position between the two methods mentioned above. With suitable parameter settings, the resulting products can also be frozen and sublimated in a sort of final-drying process.
The boiling point for liquid evaporation depends on the nature of the substance concerned and the external pressure. Reducing the pressure dramatically reduces the boiling point of the solvent and therefore avoids overheating of samples.
Key Features of Rotational Vacuum Concentration:
- No specimen foaming; minimal loss
- A large number of samples can be dried at the same time
- Samples are concentrated at the bottom or on the walls of the tube (unlike vortex shakers), which is particularly advantageous with small volumes or dilute solutions.
- Suitable for drying aqueous specimens and specimens with high solvent content.
- For volumes from less than 1ml to 2L
- Reproducible drying processes thanks to controlled process parameters such as rotor temperature (energy input for evaporation) and vacuum, include automatic setting of the optimal operating pressure according to the pump configuration
- The drying endpoint can be estimated by measuring the sample temperature and/or via the pressure rise test
- Easy and reliable solvent recovery
- DNA/RNA purification (main solvents: water, ethanol, methanol0
- Oligosynthesis; peptides
- Polymerase chian reaction (PCR)
- HPCL (main solvents: water, acetonitrile)
- Isolation/synthesis of natural substances
- Storage and handling of substances (substance libraries)
- Combinational chemistry; high-throughput screening (HTS)
- Food/environment analytics
- Toxicology and forensics
- Standard evaporation method in laboratories due to high capacity and programmable automatic process
1. Analytical Applications
Application / Industry
Toxicology / Forensic / Medicine
Amphetamines, narcotics, drugs, antibiotics, alcohols, other chemicals
(3) Soil & Sediment
Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dioxins
Food and Agriculture
(1) Residue Analysis
End product, HPLC fractions, aromas
Biotechnology & Pharmaceuticals
Specimen preparation & concentration:
Acetonitril, ethanol, methanol, water
2. Molecular Biology / Life Sciences Applications
Application / Industry
Biotechnology, Pharmaceuticals & Medicine
(1) Concentration of end product after isolation or purification
(2) Solvent removal for subsequent process steps, such as gel electrolysis, solid phase extraction (SPE), HPLC or PCR
(1) Proteins & peptides