title: Laser ablation with resonance-enhanced multiphoton ionization time-of-flight mass spectrometry for determining aromatic lignin volatilization products from biomass.
abstract: We have designed and developed a laser ablation∕pulsed sample introduction∕mass spectrometry platform that integrates pyrolysis (py) and∕or laser ablation (LA) with resonance-enhanced multiphoton ionization (REMPI) reflectron time-of-flight mass spectrometry (TOFMS). Using this apparatus, we measured lignin volatilization products of untreated biomass materials. Biomass vapors are produced by either a custom-built hot stage pyrolysis reactor or laser ablation using the third harmonic of an Nd:YAG laser (355 nm). The resulting vapors are entrained in a free jet expansion of He, then skimmed and introduced into an ionization region. One color resonance-enhanced multiphoton ionization (1+1 REMPI) is used, resulting in highly selective detection of lignin subunits from complex vapors of biomass materials. The spectra obtained by py-REMPI-TOFMS and LA-REMPI-TOFMS display high selectivity and decreased fragmentation compared to spectra recorded by an electron impact ionization molecular beam mass spectrometer (EI-MBMS). The laser ablation method demonstrates the ability to selectively isolate and volatilize specific tissues within the same plant material and then detect lignin-based products from the vapors with enhanced sensitivity. The identification of select products observed in the LA-REMPI-TOFMS experiment is confirmed by comparing their REMPI wavelength scans with that of known standards.
authors: National Bioenergy Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA. calvin.mukarakate@nrel.gov
authors: Calvin
authors: C
authors: Mukarakate
authors: Adam M
authors: AM
authors: Scheer
authors: David J
authors: DJ
authors: Robichaud
authors: Mark W
authors: MW
authors: Jarvis
authors: Donald E
authors: DE
authors: David
authors: G Barney
authors: GB
authors: Ellison
authors: Mark R
authors: MR
authors: Nimlos
authors: Mark F
authors: MF
authors: Davis
mesh_terms: D018533:Biomass; D007834:Lasers; D008031:Lignin / Q000032:analysis* / Q000737:chemistry*; D013058:Mass Spectrometry / Q000295:instrumentation*; D017785:Photons; D012399:Rotation; D014835:Volatilization
chemical_list: D008031:Lignin