Hello everyone,
I would like to ask about thermal decomposition of polystyrene using TG-QMS system - thermogravimetry coupled to quadrupole mass spectrometer. During thermal degradation of pure polystyrene material, I observe various fragments of molecules, due to styrene and benzene, but always the most intense spectrum is revealed by m/z=39. I cannot find reliable information about the source of mass, does it come from styrene or benzene fragments? Could you help me in interpretation or provide informative reference about thermal degradation of PS using TG-QMS?
I would be very grateful for your help!
39 is likely a C3H3 fragment.
do you see the parent ion at m/z=104 at all? normally, it is among the most abundant peaks.
if you use EI ionization, it may be that ionization voltage is too high so that you have excessive fragmentation.
Thank you for your answer. The QMS analyzer had an electron ionization energy of 70 eV. Yes, I observed m/z=104, but the intensity is six times less than for 39. The most intense ions are m/z=51, 39, and 50.
I agree with professor Vyazovkin. The series of ions belong to an aliphatic hydrocarbon
I recommend mass spectrometery for Smith. It is an excellent textbook in the field to explain mass spec data
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