Specialty gas mixtures consisting of carbon dioxide, oxygen and nitrogen are used for calibration of clinical blood gas analyzers. Lung diffusion mixtures are used for calibration of pulmonary function testing equipment. Anaerobic and aerobic specialty gas mixtures are used to maintain biological atmospheres in incubators for cell culture growth. Liquid nitrogen is also commonly used for freezing and preservation of biological samples.
Long term storage of clinical and biological samples is a growing application in the life science sector and Cryopreservation is the most effective way to preserve biological materials with minimal ageing. Some industries, such as artificial insemination, use liquid nitrogen freezers for long term storage of biological samples. Samples are immersed and stored in the liquid nitrogen directly at temperature of
-196°C. Materials to be stored are placed in canisters which are suspended from the top of the unit. These are then immersed in the liquid nitrogen and the nitrogen vapour.
When cyogenic samples are moved they must also be kept at extremely low temperatures. There are risks involved in transporting liquid nitrogen by hand, car or plane and therefore, dry shippers are the safest way to transport samples. Dry Shippers are dewars that are designed for the safe shipment of specimens at liquid nitrogen temperatures without the risk of spilling liquid nitrogen.
DryStore freezers separate the samples from the cryogen (liquid nitrogen) by enclosing the liquid nitrogen in a jacket around the internal sample storage chamber, minimising the risk of sample cross-contamination through the liquid nitrogen in standard liquid immersion freezers. Temperature performance down to –190°C can be achieved whilst maintaining a large lid for easy access.
Rare gases also play an important role in the clinical and life science industry. Pure Xenon is an excellent anaesthetic because it induces quick & stable anaesthesia and favours neuroprotection. In high technology medical diagnosis, such as Computed Tomography (CT) scanners, X-ray spectroscopy detectors, Nuclear Magnetic Resonance (NMR) imaging and other diagnostics applications, medical grade xenon is widely utilized. Liquid helium and liquid nitrogen are used as cooling media in Magnetic Resonance Imaging (MRI).
Lasers have become very important for many surgical applications because they are more precise and less intrusive than many alternative techniques. For example, in eye surgery for vision correction, excimer lasers are used with a gas mixture that consists of fluorine, argon, helium and neon. This laser can produce radiation in the ultraviolet range which is invisible to the naked eye but has the ability to break inter-molecular bonds within the corneal tissue of the eye during surgery to permanently improve the patient’s vision. To detect potential krypton fluoride leaks when using excimer lasers, hydrogen fluoride detectors can be used, because krypton fluoride will convert to hydrogen fluoride when it reacts with atmospheric air.