Analytical Differentiation of Recycled Content Claims and Physical Furnish in Food Contact Packaging
Analytical testing verifies physical furnish markers and migration safety, while administrative chain records prove legal recycled content claims.
ISO 15318
Standard Scope
Standardized analytical procedures define the chemical extraction and quantification of specific polychlorinated biphenyl congeners present in papermaking raw materials and finished goods. The document designated as iso 15318 specifies gas chromatographic methods to measure seven individual polychlorinated biphenyl congeners in pulp, paper and board products. These congeners correspond to IUPAC numbers 28, 52, 101, 118, 138, 153 and 180, which represent indicator compounds for historical contamination.
Contamination stems from carbonless copy paper recycling, industrial transformer fluids and legacy chemical additives embedded in post-consumer recovered paper supplies. The standard establishes clear extraction, clean-up and gas chromatography detection parameters using electron capture or mass spectrometry detection systems.
Testing Procedure
Analytical execution begins with Soxhlet extraction or accelerated solvent extraction of shredded paperboard samples using non-polar organic solvents. Extract cleanup removes co-extracted wood resins, fatty acids and synthetic sizing agents that would otherwise interfere with chromatographic separation on capillary columns. Sulphuric acid treatment or silica gel column chromatography isolates the chlorinated biphenyls from complex cellulosic extractives.
Gas chromatography columns with non-polar stationary phases separate the individual chlorinated isomers based on boiling point and chlorination pattern. Calibration standards spiked with surrogate congeners monitor recovery efficiencies, which must fall within seventy to one hundred and twenty percent for valid compliance reporting under international laboratory accreditation criteria.
Application Limit
Testing applies to recycled pulps, greyboard cartons, tissue papers and food contact board grades suspected of carrying legacy chemical residues. The standard stops short of evaluating total organic halogens or volatile monomeric contaminants, focusing exclusively on the seven target indicator biphenyls. Mills producing recycled food packaging board demonstrate compliance with statutory contaminant thresholds by running periodic audits in accordance with this protocol.
Total PCB content calculated by summing the seven indicator congeners must remain below two milligrams per kilogram of dry board to satisfy food safety recommendations issued by national regulatory authorities.