IR/UV post ionization mass spectra of (a) cytochrome c at Δt=70 s and (b) insulin at Δt=60 s. From F. Huang, X. Fan, K.K. Murray, Matrix-assisted laser desorption ionization of infrared laser ablated particles, Int. J. Mass Spectrom. 274 (2008) 21–24. doi:10.1016/j.ijms.2008.04.006.