Probing the microwave degradation mechanism of phenol-containing polymeric compounds by sample pretreatment and GC–MS analysis

We have detected the volatile organic species obtained after microwave digestion of poly(hydroxystyrene) with nitric acid in closed vessels at various reaction temperatures by using headspace solid-phase microextraction (HS–SPME) and gas chromatography/mass spectrometry (GC–MS). We probed the digestion reaction by measuring the response of the detectable species – we detected a total of 20 volatile organic compounds – with respect to the temperature over the range from room temperature to 80 °C. These compounds can be classified into alkane, alkanol, and aromatic species. The alkane species decreased monotonically, whereas the alkanol and aromatic compounds first increased and then decreased, as the digestion temperature increased. We have established the degradation mechanisms, which involve bond scission, recombination, adduct formation, and ring opening, on the basis of product analyses and bond length simulations.