Sampling Phase
Gas-phase sampling techniques extract volatile compounds from sealed sample vials under thermal equilibrium conditions prior to chromatographic analysis. Quality testing laboratories use static headspace sampling to extract residual printing solvents and volatile odor compounds from paperboard packaging. Procedures adhere to EN 13628 standards and ISO 11890 analytical guidelines for food packaging compliance.
The technique stops being effective for non-volatile organic compounds or heavy chemical additives that do not partition into gas phases.
Extraction Process
Testing specimens cut from printed paperboard are sealed inside gas-tight glass vials using crimp caps fitted with PTFE septa. Vials are transferred into thermostatted oven chambers held at constant elevated temperatures for specified equilibration periods. Heat drives volatile organic compounds out of the paperboard matrix and into the overhead gas space until thermodynamic equilibrium is reached between phases.
Automated sampling syringes draw measured gas aliquots from the vial headspace and inject them directly into gas chromatography columns. Partition coefficients govern analyte concentration ratios between the solid packaging matrix and the vapor phase. Controlling vial temperature and heating duration ensures reproducible volatile extraction efficiency.
Temperature Boundary
Exceeding vial heating temperatures above target thresholds causes thermal degradation of paperboard polymers, generating false volatile peaks. Insufficient equilibration time prevents volatile compounds from reaching true phase equilibrium, leading to underreported solvent concentrations.
