Meaning
Analytical instrumentation combining separation and high-resolution mass spectrometry enables the detailed characterization of complex polymer mixtures. Liquid chromatography quadrupole time of flight identifies additives, impurities and degradation products with extreme mass accuracy. The system first separates the components based on their chemical properties before measuring their mass-to-charge ratios.
This technique is the standard for detecting non-intentionally added substances in food-contact plastics.
Molecular Identification
Accurate mass measurements allow for the determination of the elemental composition of an unknown molecule. Using liquid chromatography quadrupole time of flight, lab technicians can distinguish between two compounds that have nearly identical weights. This capability is essential for verifying that a resin supplier has used the correct antioxidant or UV stabilizer.
The resulting data provides a detailed chemical fingerprint of the material.
Trace Detection
Sensitivity levels of modern detectors allow for the identification of contaminants at parts-per-billion concentrations. When a part fails due to unexpected embrittlement, liquid chromatography quadrupole time of flight can find the trace amounts of a catalyst residue or a cleaning agent that caused the issue. This level of detail is beyond the reach of standard infrared spectroscopy.
The ability to find such small quantities makes it a primary tool for root cause analysis in polymer failure investigations.
Quantitative Precision
Measuring the intensity of the signals provides information on the amount of each substance present in the sample. Although primarily a qualitative tool, liquid chromatography quadrupole time of flight can be used for semi-quantitative analysis when compared against known standards. This information helps moulders ensure that additive levels remain within the safety and performance limits specified by the end-user.
Detailed reports from this analysis support the regulatory compliance of medical and food-grade plastic components. This method is the ultimate defense against chemical contamination in sensitive production runs.
