What Are Glass Capillary Tubes?

Precision Glass Capillary Tubing

Calibrated Accu-Glass Capillary Tubes

Accu-Glass manufactures custom designed small diameter thin-walled precision glass capillary tubes which, by design, exhibits capillary action. Capillary action is the movement of a liquid into a tube based on its surface tension. Heavy-wall or thin wall capillary tubing can be color coded to designate volume calibration, fill line or CV accuracy (coefficient of variation), or coated with heparin (an anticoagulant). Capillary tubes are great for liquid measurement, liquid transfer and sample collection applications. Accu-Glass manufactures capillary glass tubing from molten glass drawn it into long lengths. These are then cut to a specific length and the ends of the tubes are flame polished. Many times the tubes are marked with a color coded fill line to designate volume calibration for applications like disposable glass micropipettes. In the case of blood collection tubes (called hematocrit tubes), these are processed in the same manner; however, some are coated with heparin (an anticoagulant) so that blood does not clot when drawn. Finally, Accu-Glass can package the tubes in the final consumer packaging or bulk pack when our customers prefer to final package themselves.

Glass Capillary Tube Features

  • Precision ID Tolerance to ± 0.0001″
  • Custom volumetric size capabilities
  • Standardized custom sizes
  • Precision Volumetric Marking Measures
  • Chemically and physically unaffected by sterilization
  • Inert and non-reactive with most drugs, bodily fluids, or gases
  • Safe for direct human contact

Glass Capillary Tube Applications

  • Micro Dispensing medication delivery
  • Clinical testing or blood sample collection
  • Hematocrit Glass Capillary Tubes for blood collection
  • Disposable “Marked” Glass Micropipettes
  • Micropipette for precise predetermined volume dispensing (aliquot)
  • Capillary spotters for depositing small amounts of a sample onto a TLC (thin layer chromatography) plate