EN 645

Extraction Protocol

European standard en 645 provides a set of procedural requirements for the preparation of cold water extracts from paper and board materials intended for food contact applications. This methodology establishes how laboratories extract chemical components from a substrate to evaluate potential migration into food products. The standard excludes procedures for determining substances that might migrate through gaseous phases.

Proper application requires the immersion of the paper sample in distilled water at a specified temperature and duration. The aqueous extract then undergoes analysis to quantify concentrations of soluble materials. Laboratories must ensure that the water quality meets high purity levels to prevent contamination.

Analytical Boundary

The technical scope of en 645 focuses on the preparation phase rather than the subsequent chemical detection methods. Testing facilities apply this procedure to verify that paper additives, sizing agents, or residual process chemicals remain within established safety thresholds. Consistent extraction ensures that analytical results remain comparable across different testing facilities.

A failure to control the ratio of surface area to water volume alters the migration rate and invalidates the assessment. Practitioners use this preparation method as a baseline for further toxicological screening of finished packaging. Rigorous temperature regulation during the soaking phase prevents the degradation of thermally sensitive analytes.

If the material exhibits high permeability, the extraction time adapts to reflect potential real-world exposure scenarios. Accurate results demand strict adherence to the specified agitation frequency during the soaking period. The volume of the extract dictates the capacity for subsequent detection limits.

Substrate Influence

Finished paper and board products frequently contain coatings or functional layers that react differently to water exposure. The procedure accounts for these differences by defining how to prepare samples that feature single-sided or multi-sided contact. Testing verifies whether coatings release components that exceed regulatory safety limits for consumer protection.

A high level of uniformity in the preparation of these extracts creates a reliable foundation for regulatory compliance audits. Finished packaging that adheres to these extraction protocols demonstrates a commitment to material safety and chemical stability.