Extended Data Figure 8. Laser ionization analogue spectrum of pyrene in water/acetic acid.
Cationic TOF mass spectrum recorded with the liquid microbeam ionization setup (Methods 8, ED Fig. 9) containing 0.1 % pyrene dissolved in a mixture of water and acetic acid. The laser pulse simulates an ice grain impact with a speed of about 10 km/s 78. All features marked as “pyrene fragment” do not appear up in the blank experiment with just the solvent mixture and are either direct pyrene fragments or cations formed from pyren fragments clustering with the solvent (e.g. at 159 u).
The molecular mass lines of pyrene are about 10 times more abundant than any fragments, indicating the stability of the PAH molecule. An isolated benzene ring fragment (77 u or 91 u) as in CDA HMOC spectra does not form.