The detection or analysis of the gases evolved during a chemical reaction, as a function of temperature, constitute the techniques of thermal analysis called evolved gas detection (EGD) and evolved gas analysis (EGA), respectively.
Thermal analysis using mass spectrometry covers a large number of related and analytical powerful techniques such as evolved gas analysis using mass spectrometry (EGA-MA) including termogavimetry-mass spectrometry (TG-MS), temperature programmed pyrolysis-mass spectrometry and temperature programmed desorption mass spectrometry.
In conventional EGA-MS, the evolved gaseous products, which are introduced rapidly to MS, are generally ionized by electron ionization (EI) at 70eV. In this case, a part of the evolved gaseous molecular ion undergoes further decomposition, and observed simultaneously ions. Especially in the thermal processes, since the evolved gases consists of multiple gaseous species in almost all cases, the resulting fragment ions are overlapped, while the fragment ions provide significant information concerning the structure of the molecule, the apparent mass spectra can be quite complicated. In order to differentiate in real-time the multiple organic species that are evolved in the thermal process, one feasible approach is the use of MS with a selective and soft (fragment-free) ionization technique which avoids fragmentation during ionization.
Differential thermogravimetry photoionization mass spectrometer simultaneous measurement system （ThermoMass Photo）can detect the molecular ion without fragment, the system is applied the gaseous detector to photoionization mass spectrometer which coupled with TG-DTA-MS.
There is a lot of trouble when a drug or polymer absorbs more moisture than appropriate, such as poor appearance, component change and deterioration of mechanical and physical property. Hence, it is important to know how much water is including in these samples.
In present work, we evaluated amount of water in flour, drug and polymer employed ThermoMass Photo.
Evolved gas analysis products from Rigaku
In TG-FTIR, gases evolved by volatilization or thermal decomposition are qualitatively analyzed, which allows you to track changes in the generated amount along with the temperature change.