Structural characterisation of macromolecular organic material in air particulate matter using Py-GC-MS and solid state C-13-NMR

Organic air particulate matter was analysed by applying the techniques of P y-GC-MS (pyrolysis-gas chromatography-mass spectrometry) and solid state C- 13-NMR (nuclear magnetic resonance). Particles dislodged from air particula te filters and humic acid extracted from these filters were studied for str uctural components. The structural components of the air particles and extr acted humic acid consisted of compounds originating from biomacromolecules, namely, lignin, carbohydrates, protein and lipids. The main components ide ntified for each class included: (1) methoxyphenols originating from lignin ; (2) furans, aldehydes and ketones from carbohydrates; (3) pyrrole, indole s from protein; and (4) many hydrocarbons from lipid structures. Single ion monitoring (SIM) and tetramethyl ammonium hydroxide (TMAH) methylation wer e utilised for detection of aliphatic hydrocarbons and acidic components, r espectively. Hydrocarbons ranging from C-9 to C-28 were detected by SIM ana lysis, while aliphatic acids ranged from C-9 to C-18. The majority of compo nents analysed directly in the air particles were similar to those from the humic acid extracts. Many of the structural components of air particles we re typical of humic substances of soil and aqueous systems and these were a ttributed to both biogenic and anthropogenic sources.