Glass Test Tubes

Glass test tubes are a staple of every working laboratory, and SmartLabs stocks a full range to suit schools, universities, research facilities and medical labs across South Africa. The collection covers borosilicate glass test tubes, soda-lime glass test tubes, and plastic-capped options, in popular sizes from 10 x 75 mm up to 25 x 150 mm, with both rimmed and rimless styles available.

Borosilicate glass is the material of choice for most laboratory applications. It resists thermal shock, tolerates direct flame and autoclave sterilisation, and holds up against a wide range of chemicals, making it the right call for heating reactions, culturing microorganisms, or any work where contamination and breakage carry a real cost. Soda-lime glass test tubes cover lighter-duty general use and are a cost-effective option for high-volume school lab sessions.

The rimmed style gives you a secure grip point for clamps and makes it straightforward to fit stoppers, cotton plugs or caps. Rimless tubes have fire-polished openings that are easier to stack and clean, and pair well with standard test tube plugs. Capped options keep samples sealed for storage or transport.

All orders ship nationwide from the SmartLabs warehouse in Boksburg, Gauteng. Buy in single packs or in bulk, online, with no minimum order.

What is a Glass Test Tube?

A glass test tube is a simple cylindrical vessel, closed at one end and open at the other, used for holding, mixing, heating, and storing small samples. Borosilicate glass 3.3 test tubes have a very low coefficient of thermal expansion, resisting sudden temperature changes, and are resistant to most acids, alkalis, and solvents. They can be autoclaved and heated directly over a Bunsen burner. Soda-lime glass tubes are more affordable for general use where heat or chemical exposure is not a factor. Rimmed tubes have a rolled lip for clamps and stoppers; rimless tubes have a fire-polished opening for easy stacking. Round-bottom tubes distribute heat evenly; flat-bottom tubes stand upright without a rack.

Common uses of laboratory glass tubes in the lab

From growing cultures to serial dilutions, heating reactions, and colorimetric analysis, glass tubes are the workhorse of individual sample handling across every scientific discipline.

  • Culture and microbiology

    Test tubes and culture tubes are the standard vessel for growing microbial cultures, performing broth dilution series, and incubating biological samples. They can be fitted with loose-fitting caps or cotton wool plugs to allow gas exchange, and can be autoclaved repeatedly for sterile reuse.

  • Serial dilutions and sample preparation

    Glass test tubes are the preferred vessel for serial dilutions in microbiology, clinical pathology, and analytical chemistry. Their uniform bore allows accurate pipetting, and a rack of identically sized tubes allows multiple dilution factors to be prepared simultaneously.

  • Heating and chemical reactions

    Borosilicate glass tubes withstand direct Bunsen burner flame for heating small liquid samples, dry distillations, and qualitative chemical reactions. Boiling tubes have a thicker wall for more vigorous heating applications.

  • Colorimetric comparison

    Nessler tubes are tall flat-bottomed glass cylinders for visual colorimetric analysis, where an unknown sample is compared against concentration standards viewed through the liquid column. Used in water quality testing, ammonia determination, and environmental monitoring.

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