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ABC of Safety in the Biological Sciences
AMPOULE
A small sealed glass container used for the preservation of a measured quantity of sterile compound or solution. It is used principally for injectable, parenteral solutions or drugs but is also used for storage and transport of test reagents and premeasured quantities of chemicals, and has been used for the storage of microorganisms in liquid nitrogen.
Osmium tetroxide and gold chloride are examples of chemicals which are received in glass ampoules. Osmium tetroxide is commonly used in electron microscopy laboratories for the fixation of body tissues prior to processing and gold chloride is commonly used in histology laboratories for toning paraffin sections after staining with silver compounds.
Ampoules easily slip and roll and may fall to the floor and break unless care is taken with their handling. Unpack ampoules over a bench and well away from its edge. If freezing will not damage the contents, spillages can often be avoided if the contents are frozen before opening the glass ampoule. To open make a small scratch on the neck of the ampoule, touch the scratch with a hot wire or hot glass rod and the rapid expansion in the area will cause the neck to separate. Always wear gloves when breaking off the top of an ampoule and take the necessary precautions appropriate to the chemical contained in the ampoule when handling the contents.
If the ampoule contains a solid chemical which is known to be hazardous to human health and which is normally used diluted in aqueous solution, thoroughly clean the outer surface of the ampoule then wash with several changes of glass distilled water. Place the cleansed, intact ampoule, with its contents, into a clean reagent bottle. Add to the reagent bottle the required amount of dilutent and then carefully break the glass ampoule with a rod in the reagent bottle. This task is normally performed in a fume hood and with the individual wearing protective clothing appropriate to the nature of the chemical contained in the ampoule.
Fisher Scientific offer for sale a "Safesnap Ampoule Collar" made from non-breakable polyethylene that allows the fracture of glass ampoules with complete safety. The collars are disposable and are meant to be used once only so that cross contamination does not occur. The collar is manufactured in two sizes (i) for 1-4 ml ampoules and (ii) for 5-10 ml ampoules.
Ampoules are not recommended for the storage of microorganisms in liquid nitrogen. There are reports of ampoule explosions causing severe eye injuries and inoculation of microorganisms into body tissues. Pre-sterilised polypropylene tubes with high density polyethylene caps with silicone washers are better suited to the storage of microorganisms in liquid nitrogen. Heat sealable polypropylene tubes are also available (Nunc).
References
Bennington, J.L. (Ed.) (1984)
Saunders Dictionary and Encyclopaedia of
Laboratory Medicine and Technology.
W.B. Saudners Co., Philadelphia, U.S.A.
Fisher Chemical Co. (1988)
Fisher 208 Catalog.
Fisher Scientific International Springfield,
New Jersey, U.S.A.
Miller, B.M. et al. (1986)
Laboratory Safety: Principles and Practices.
American Society for Microbiology, Washington
DC, U.S.A.
Nunc Inter Med (1989)
Nunc Cryo System.
Post Box 280, Kamstrup, DK4000 Roskilde,
Denmark.
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