Cramer Structural Classification Tiers for Non-Intentionally Added Substances
Assigning non-intentionally added substances to Cramer tiers determines analytical screening limits, where Class III migrants require migration caps under 90 ppb.
Semi-Quantitation
Meaning
An analytical method used to estimate the concentrations of chemical compounds in a sample without using a fully validated calibration curve for every individual analyte is used to screen polymer extracts for unknown substances. This semi-quantitation provides a fast way to evaluate the additive profile and trace contaminants in a raw polymer batch. By comparing the signal response of unknown compounds to a single internal standard, laboratory technicians can approximate the concentration of multiple compounds in a single run.
This process is highly valuable during initial material screening.
Analytical Approximation
Gas chromatography combined with mass spectrometry is the most common technique for identifying volatile compounds in polymer extracts. When using semi-quantitation, the results have a higher margin of error than traditional quantitative tests but remain sufficient for risk assessment. This approach is highly efficient for analyzing complex polymer formulations that contain many additives.
Sourcing Safety
Regulatory compliance of food contact materials depends on proving that specific substances do not migrate above allowed thresholds. Since running full quantitative calibrations for every trace additive is prohibitively expensive, semi-quantitation acts as a preliminary filter to identify substances of concern. This screening reduces the total cost of materials testing.
Analytical Limitation
Inaccuracies can arise when the ionization efficiency of the target compound differs significantly from the internal standard. This limitation of semi-quantitation can lead to underestimating the concentration of some migratable substances. Fully validated methods are required if a borderline result is detected.