Direct probe CI-MS and APCI-MS for direct materials analysis

Direct probe in vacuo chemical ionization (isobutane CI-MS) and Pyroprobe atmospheric pressure chemical ionization (APCI-MS) are complementary techniques for the analysis of polymeric materials. Both techniques can generally be used to detect residual chemicals and more volatile additives (via thermal desorption), as well as polymeric components (via pyrolysis).Isobutane CI-MS is often a “softer” technique than APCI-MS, giving less background, less fragmentation, and more predictable and reproducible spectra. APCI, on the other hand, provides a higher maximum temperature and a means to carry out sample heating at atmospheric pressure (to simulate TGA). Pyroprobe APCI with high performance instruments has the added features of high resolution mass measurement (to determine atomic compositions) and tandem mass spectrometry (MS/MS, to obtain fragmentation patterns).