What is the volume of the Microcapillary tube?

Volume of a Microcapillary Tube

The volume of a microcapillary tube, a slender tube used in various scientific and medical applications, can be calculated based on its internal dimensions. These tubes are essential for handling small volumes of liquids, often in microliters (μL) or nanoliters (nL), and are widely used in laboratories for tasks such as blood sampling, microfluidics, and the manipulation of small organisms.

Calculation Method

To calculate the volume of a microcapillary tube, you need to know the internal radius (r) of the tube and its length (L). The volume (V) can be calculated using the formula for the volume of a cylinder, which is:

V = πr2L


  • V is the volume of the tube,
  • r is the internal radius of the tube, and
  • L is the length of the tube.

It's important to ensure that the radius and length are in the same unit of measurement when performing this calculation to obtain the volume in cubic units (e.g., cubic centimeters, cubic millimeters).

Example Calculation

For instance, if a microcapillary tube has an internal radius of 0.5 mm and a length of 50 mm, the volume can be calculated as follows:

V = π(0.5 mm)2(50 mm) = π(0.25 mm2)(50 mm) ≈ 39.27 mm3

Since 1 mm3 is equivalent to 1 μL, the volume of this microcapillary tube would be approximately 39.27 μL.

Practical Considerations

In practical applications, the exact volume of a microcapillary tube may also depend on factors such as the tube's material, the precision of its manufacture, and the surface tension of the liquid being measured. Manufacturers often provide specific volume information for their microcapillary tubes, taking into account these variables.

For detailed specifications and volume information on specific microcapillary tubes, it's advisable to consult the manufacturer's documentation or product listings, such as those available on Sigma-Aldrich's website.

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