Gaseous Equilibration
A sample preparation and gas extraction technique determines the concentration of volatile organic compounds by analyzing the air above a sealed specimen. In packaging laboratory testing, static headspace analysis is used to measure the level of residual solvents left in printed paperboards and laminated films. The technique relies on the thermodynamic equilibrium established between the solid or liquid sample and its surrounding vapor phase inside a closed container.
This process separates the volatiles from the non-volatile substrate without requiring direct liquid extraction.
Instrumental Method
Automated testing instruments heat the sealed sample vial to a specific temperature for a set duration to accelerate the release of volatile compounds. In the process of static headspace analysis, a portion of the equilibrated gas is drawn from the vial headspace and injected into a gas chromatograph for separation. This method keeps the chromatograph injection system free from polymer residues and ink pigments that could contaminate the column.
Consistent temperature control is necessary to achieve reproducible partition coefficients.
Industrial Application
This technique is widely used for routine quality checks on flexographic and gravure printing runs. It ensures that packaging batches are screened quickly and efficiently before being released for distribution to customers.
