Helium Pycnometry

What is it?

This technique allows the volume occupied by a given amount of material to be determined by comparing the gas pressure variation inside the sample chamber against a volume calibrated one. Helium is commonly used for this test because, apart from being an inert gas, it penetrates easily through the pores of the sample and is thus capable of determining the solid volume much more accurately.

What is it used for?

Helium pycnometry is used to determine the real (true) density and volume of materials. The real density of a sample is defined by the ratio between the mass of material and the respective real volume that it occupies, thus excluding all empty spaces and considering that there are no closed pores inside the particles.

Equipment and working conditions

To determine the real density the laboratory uses an AccuPyc 1330 model from Micromeritics.

Example of use

Real density is a very important parameter for the characterisation and development of products and can be applied to various non-volatile solid or liquid materials in several areas such as the food industry, pharmaceuticals, catalysis, polymers and minerals, etc.