Culture tubes, sample tubes or test tubes are an important part of laboratory glassware or plasticware which is open at the top and closed at the bottom.
Glass is the preferred choice of material for test tubes used in scientific laboratories because they’re well resistant to heat. Materials like borosilicate glass or fused quartz can resist high temperatures up to many hundred degree celsius and also, resistive to many chemicals.
The various length of tubes used in scientific laboratories ranges from 50 to 200 mm long and 10 to 38 mm wide. There are various types of test tube bottoms: flat, round and conical also they can be plain or graduated.
Plain Test tubes with a round bottom are widely used in various industries e.g. Biology Lab, Pathology, Science, School, University, Home Decor etc. A screw cap test tubes are also known as culture media tubes which can be reused and autoclavable. A ground glass stoppered test tubes are generally graduated. Test tubes play a crucial role in qualitative experiments and assays. The design of the test tube was made in a way that mass loss is reduced when pouring the content out of the test tube, making it easier to monitor as well as clean. Test tubes are narrow because a narrow design prevents the contents of the tube-like gasses from spreading into the environment.
Types of test tubes if classified on the basis of materials are:
Glass test tubes:
Glass test tubes are preferred because they’re thick-walled chemical resistant and/or heat resistant. Glass and plastic tubes are mostly reusable and autoclavable also more clear and have better visibility.
Applications that require good, long-term thermal stability will benefit the most from Fused silica.
Borosilicate glass works the best for chemical applications because they can withstand thermal shock and chemical attack.
Quartz glass is highly resistant to thermal shock and has high transmission of infrared radiation (IR).
Plastic test tubes:
Plastic test tubes are lighter in weight and generally cheaper than glass tubes. Some plastic test tubes are also resistant to ultraviolet (UV) light and pressure.
Fluoroelastomer materials have poor low-temperature performance but good heat, oil and chemical resistance.
Neoprene tubes resist degradation from UV light and are useful over a wide range of temperatures.
Nitrile is a good choice for low-temperature applications because it has a suggested operating range of -30°F to 275°F.
Nylon and polyamide materials have higher tensile strength as well as good pressure ratings.
Polyethylene (PE) test tubes are somewhat opaque, have excellent chemical resistance, but poor temperature resistance.
polypropylene (PP), polytetrafluoroethylene (PTFE), polyurethane (PU), and polyvinyl chloride (PVC) are some of the materials used for making plastic test tubes.
Types of test tubes if classified on the basis of usage are:
- Boiling test tubes: are specially made with materials that can easily withstand high temperatures.
- There areculture tubesspecially made for storing cultures, water and gases. A test tube that has a stopper is used to safely store culture as well as chemical and biological samples.
- Ignition test tubes: Ignition test tubes are similar to boiling test tubes but are smaller and thinner than the boiling test tubes which makes them difficult to clean but they are disposable.