Vacuum evaporation

Applications overview: vacuum evaporation

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 temperatures for evaporation and operate at nearly atmospheric pressure or vacuum levels down to approximately 100 mbar.
  • 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 1 ml to 3 litres
  • Reproducible drying processes thanks to controlled process parameters such as rotor temperature (energy input for evaporation) and vacuum, including 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

 
Applications overview

  • DNA/RNA purification (main solvents: water, ethanol, methanol)
  • Oligosynthesis; peptides
  • Polymerase chain 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
ApplicationSubstances
Toxicology / Forensic / Medicine
Residue analysis Amphetamines, narcotics, drugs, antibiotics, alcohols, other chemicals
Environment

Residue analysis:

  • Water
  • Wastewater
  • Soil & sediment
Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dioxins
Foods and agriculture
  • Residue analysis
  • Quality control
  • Purity control
End product, HPLC fractions, aromas
Biotechnology & pharmaceuticalsSpecimen preparation & concentration: before or after HPLCAcetonitril, ethanol, methanol, water
2.Molecular biology applications / Life sciences
Application / IndustryApplicationSubstances
Biotechnology, pharmaceuticals, medicine
  • Concentration of end product after isolation or purification
  • Solvent removal for subsequent process steps, such as gel electrolysis, solid phase extraction (SPE), HPLC or PCR

 

  • Proteins & peptides
  • Oligonucleotides
  • DNA/RNA