Preparative TREF and Size Exclusion Characterization of Olefin Oligomers
Preparative TREF combined with high-temperature SEC isolates and quantifies migrating sub-1000 Da polyolefin oligomers to verify food contact safety compliance.
N Alkane Standards
Meaning
Reference mixtures of straight-chain hydrocarbons are employed in gas chromatography to establish a standardized scale for identifying volatile compounds released from heated plastics. These n alkane standards allow laboratories to calculate retention indices that are independent of specific column dimensions or instrument flow rates. This calibration is critical for tracking volatile organic emissions and residual monomers in food-contact polymer grades.
Calibration Method
Injecting the hydrocarbon mixture before or during sample analysis generates a series of regularly spaced reference peaks across the chromatogram. By comparing the elution times of unknown polymer outgassing products against those of the n alkane standards, the analytical software assigns a relative retention index to each compound. This step removes the variability introduced by temperature fluctuations and column aging, providing reproducible data across different laboratories.
Volatile Identification
Pinpointing the origin of odors or safety hazards in molded products depends on the accurate identification of volatile components. Utilizing n alkane standards enables compounders to identify trace degradation products or remaining solvents that might affect the taste or safety of packaged contents. This identification allows for targeted adjustments to the injection molding process or the resin compounding formulation.
Standard Composition
Formulations of these reference materials cover a specific carbon number range tailored to the volatility of the target analytes.