Meaning
Classification for a group of heavy hydrocarbons identifies mineral oil saturated hydrocarbons that move from packaging materials into food products. This c16 to c35 carbon range represents the fraction of petroleum distillates that the human body cannot easily eliminate.
Migration Limit
Migration depends on the thickness of the polymer barrier and the temperature of storage. Polyethylene and polypropylene allow these small molecules to pass through the amorphous regions of the polymer matrix. High-density grades with higher crystallinity offer more resistance than low-density resins.
Analytical Identification
Gas chromatography separates the hydrocarbons by their boiling points to create a profile of the contaminants. A broad hump in the chromatogram indicates a complex mixture of branched and cyclic alkanes. Comparing this signal to a known standard allows for the quantification of the specific oils present in the sample.
Barrier Efficiency
Functional barriers like aluminum foil or specialized co-extruded films stop the movement of hydrocarbons entirely. Using a layer of ethylene vinyl alcohol can reduce the migration of the c16 to c35 carbon range by several orders of magnitude. Cost remains a factor in choosing these multi-layer structures over simple monolayer films.
This selection process balances the safety of the consumer against the production price of the flexible packaging.
