Laboratory technicians and scientists regularly use vacuum pumps (frequently of the bench-top variety) for a range of tasks including aspirating/filtering, controlling or inducing solvent evaporation in concentrators, as well as in gel driers, vacuum ovens, desiccators and rotary evaporators.
Vacuum Pump uses in laboratory
Despite aspiration, filtration and the control for solvent evaporation accounting for the many laboratory pump usages, possibly one of the most cutting-edge use of vacuum pumps in the laboratory is in the field of mass-spectrometer (MS). These tend to be stand-alone units, which are about the size of a domestic refrigerator but can be bench-top, and incorporate the MS part and the vacuum pump in the same module.
Whilst at the high-value end of the laboratory vacuum pump systems, the pumps associated with these MS units are very much at the vanguard of the vacuum industry in terms of automation, control, compactness, effectiveness, efficiency, quiet operation and low-maintenance and cost effectiveness.
MS enables the near-immediate identification and measurement of thousands of types of molecules (e.g. metabolites, lipids, proteins, small molecules etc). MS allows this to be achieved without the use of expensive reagents, whilst also providing a detailed picture of biology, and how cells and tissues respond to drug treatment.
It is impossible to underestimate the importance of MS in terms of both cutting-edge technologies in bio-medical science, but also in terms of spin-off technology in the more generalist field of laboratory high vacuum pumps.
Mass spectrometers: scientific pioneers
By using high-end mass-spectrometer detection and ionisation technology in combination with sample preparation and analytical workflows (tailored to drug discovery), it is possible to obtain biological fingerprints/signatures and measure pharmaceutical responses to a broad range of biological samples.
By applying MS in combination with other technologies, it has been possible to make significant advances in a number of important medical fields including: the characterisation of advanced cell models; biomarker identification; drug distribution/tissue penetration; and isotope tracing.
To achieve such goals, scientists have invested in cutting-edge, direct-from-sample mass spectrometry technologies that enable them to rapidly measure biological ‘signatures’ from scarce molecular samples, as well as look for spatial changes in drug and metabolite distribution. In addition, to providing the highest possible resolution, they have employed more traditional MS methods (using liquid chromatography) to reduce the complexity of biological samples for analysis.
MS has several significant sub- disciplines, all of which rely upon vacuum technology, these include: electrospray ionisation (ESI); desorption electrospray ionisation (DESI); rapid evaporative ionisation mass spectrometry (REIMS); and acoustic mist ionisation mass spectrometry (AMI-MS). All these highly specialised fields are helping to roll back the mysteries of the effectiveness of drug treatments and bio-medical science in general…and yet they all rely upon the humble vacuum pump.
Factors to consider when choosing a vacuum pump
Technicians and scientists have traditionally relied upon oil-sealed rotary vane vacuum pump units for their laboratory work. However, these require regular oil top-ups, are relatively expensive to run, require regular maintenance and also (despite up-dated oil filter hardware) invariably pass some oil-mist out into the immediate atmosphere.
There are a number of logical steps to determine the ideal vacuum laboratory pump, with the “dry” (i.e. oil-free) as emerging as the pump of choice:
- Evaluate the pump application (and by inference the pressure range) that the pump will be required to service. By cross-referencing against a pressure-range chart, it is possible to determine the pump choices available.
- Laboratories are frequently almost monastic in terms of being a quiet environment in which to work, and as such, a noisy pump would be a complete anathema to such a harmonious, working environment.
- It is very likely that any contamination, either in the gases being processed or those being expelled, would be at a variance with the task in hand. This is especially true of oil-sealed rotary vane pumps, which by their very nature insert small quantities of oil into the process gas (however, efficient the oil-mist filter elements may be). Furthermore, captured and recycled oils will need to be condensate-purged, which is likely (however much care and high-tech engineering is involved) to release at least some oil-mist into the laboratory environment. ”Dry” pumps are increasingly preferred.
- Size, control and footprint are three inter-connected factors that need to be considered when choosing a laboratory vacuum pump system. Too large a pumping unit will mean an unnecessarily large footprint but more importantly, such large units are difficult to control if only specific (and small) flows are required.
- Costs, in terms of both the initial investment, on-going energy costs and maintenance costs, both in terms of consumables (oil changes), disposables (filter elements) and man-power, need to be taken into consideration.
conclusion
Oil-sealed rotary vane pumps are well established for laboratory vacuum generation, primarily due to their proven technology, their reliability, and low cost. However, their dominance in this field is being over taken by the significant advantages of “dry” pumps, (i.e. oil-free) that do not contaminate either the process gases or the surroundings. The advantages of such dry pumps include: low noise, zero oil contamination of the gas flow (and of the surrounding atmosphere), long service intervals and no need for costly oil replacement and disposal.
Choosing the right vacuum pump will enhance the environment, the convenience and the productivity in a laboratory. However, making a poor choice will likely interfere with scientific objectives, lead to substantial maintenance demands and an unpleasant working environment.
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