Some of the most
popular types of laboratory gas generators are discussed here:
The concept of laboratories
have changed with time. Today with the
advent of newer technologies a modern lab makes the life of technicians
working there much comfortable. Gone are the days of bulky gas cylinders and
their place is taken by the much more sophisticated technique of on site
laboratory gas generation. The whole range of generators have found use in a
host of laboratory applications that include pharmaceutical as well as
medical laboratory equipment. These generators comes with numerous types of
flow rates, purities and pressures to suit different application. Also, they
can be available with or without the provision of internal air supply. One
of the potential advantages of using gas generators in laboratories is that,
it avoids having gases at high pressure which can sometimes lead to hazards.
Why Laboratory Gas Generators?
The laboratory gas generators offer
the following advantages:
- Better Health & Safety –Just imagine this scenario,
in a laboratory a high pressure cylinder containing nitrogen gas gets
abruptly vented to the atmosphere. As a result approximately 9000litres
of unbreathable gas gets released. It can very well lead to
asphyxiation. This is one of the primary reason for shifting to on-site
gas generators. With the lab gas generators there is n o question of
manual handling of the bulky gas cylinders. Also, there is no
involvement of connection/ disconnection of high pressure regulators.
Further there is the provision of an automatic shutdown if there is any
downstream leakage.
- Improved Productivity – A situation where sample is lost
because the cylinder has run out would never happen with lab gas
generators.
- Simplicity of Use – Very easy operation involves only
pushing start buttons. Gas generators are easy to maintain that can be
planned before hand.
- Cost Advantages – Compared to the gas supply through
cylinders, gas generators cost a fraction of that. As in cylinders there
is not only the cost of gas which can be seen but expenditure in the
form of transportation, inventory control, booking orders and and
downtime for changing over to new cylinders.
- Storage Advantages - In case of gas cylinders because of
safety concerns there is need for ample storage space as hydrogen
cylinders need to be kept at a distance from the oxidizing gas
cylinders.
- Purity Factor - Laboratory gas generators generate very high
quality analytical gases from an on-site source effectively removing
hydrocarbons and carbon dioxide. Lab generators sometime comprise a
hydrogen purifier, produced from palladium. This Palladium shows
remarkable property of permitting only hydrogen to disperse through it.
Thus resulting in utmost purity of hydrogen gas. To give another
example, nitrogen generators using hollow fibre membrane are widely used
in Liquid chromatography - Mass spectrometry applications. This
membrane effectively breaks compressed air into nitrogen and an
oxygen-rich stream – containing undesirable impurities in the form
of water vapour.
- Greater Compatibility - The lab generators display
compatibility with most of the major analytical instruments thus
resulting in increased stability and better reproducibility of results.
Common Gas Generation Techniques
Popular
ways of gas generation technologies are PSA (pressure swing adosrption),
VPSA( vacuum pressure swing adsorption), membrane based separation,
cryogenic, endothermic, exothermic,etc. Out of this, due to environmental
and convenience factors, PSA or pressure swing adsorption is proving to be a
popular technology being used as laboratory gas generators. A simple digram
illustrating the PSA process as utilised in Air generators is shown in the
diagram.
Applications of Laboratory Gas Generators
Laboratory gas generators
are an integral part of research laboratories being used in critical
analytical instruments. Some of these high end applications given below
include the usage of high purity gases.
- Liquid Chromatography/Mass Spectrometry (LC/MS)
- Inductively coupled plasma spectrometer(ICP)
- Gas Chromatography/Mass Spectrometry (GC/MS)
- Total organic carbon analyzer
- Atomic absorption(AA) spectrometer
- Total Hydrocarbon Analysis (THA)
- Thermal Gravimetric Analysis (TGA)
- Fourier Transform Infrared (FT-IR) Molecular Spectroscopy
- Nuclear Magnetic Resonance (NMR)
- Evaporative Light Scattering Detection (ELSD)
- Total Inorganic Carbon analyzer (TIC)
