Mineral Oil Findings in Recycled Fibre Food Packaging
Recycled paperboard packaging requires verified functional barriers and HPLC-GC-FID test dossiers to prevent gas-phase MOSH and MOAH food contamination.
Alumina Fractionation
Purification Procedure
Adsorption chromatography provides the mechanism for isolating mineral oil components from complex packaging extracts. Using alumina fractionation, a laboratory separates saturated and aromatic hydrocarbons by exploiting their different affinities for a polar stationary phase. Activated aluminum oxide acts as the sorbent within a glass column or a solid phase extraction cartridge.
Hexane or similar non polar solvents move the analytes through the media at controlled rates.
Sorbent Activity
Chemical activation of the aluminum oxide ensures that the surface area remains available for binding interfering lipids and waxes. The alumina fractionation process requires precise control of water content in the stationary phase to maintain consistent retention times for the mineral oil fractions. Any moisture in the air or the solvent can deactivate the sites and cause the saturated hydrocarbons to elute with the aromatics.
This loss of selectivity prevents accurate quantification.
Purification Yield
Removing fats from recycled board extracts is the primary application for this technique in food safety testing. It allows the analyst to clean up the sample before it reaches the gas chromatograph, protecting the capillary column from contamination and reducing the baseline noise. Without this step, the unresolved complex mixture would be obscured by heavy triglycerides and vegetable oils from the paper manufacturing process.
The cleanup provides a clear signal for the fractions that require measurement against legal limits.