A.S. Woods, M.V. Ugarov, S.N. Jackson, T. Egan, H.-Y.J. Wang, K.K. Murray, J. A. Schultz, “IR-MALDI-LDI combined with ion mobility orthogonal time-of-flight mass spectrometry,” J. Proteome Res. 5 (2006) 1484–1487. doi:10.1021/pr060055l.
Most MALDI instrumentation uses UV lasers. We have designed a MALDI−IM−oTOF−MS which employs both a Nd:YAG laser pumped optical parametric oscillator (OPOTEK, λ = 2.8−3.2 μm at 20 Hz) to perform IR−LDI or IR−MALDI and a Nd:YLF laser (Crystalaser, λ = 249 nm at 200 Hz) for the UV. Ion mobility (IM) gives a fast separation and analysis of biomolecules from complex mixtures in which ions of similar chemical type fall along well-defined “trend lines”. Our data shows that ion mobility allows multiply charged monomers and multimers to be resolved; thus, yielding pure spectra of the singly charged protein ion which are virtually devoid of chemical noise. In addition, we have demonstrated that IR−LDI produced similar results as IR−MALDI for the direct tissue analysis of phospholipids from rat brain.