Background Aerosols are studied for –Environment impact Direct climate effect Indirect climate effect –Biofuels –Human health impact Medicinal Cigarette smoke Direct effect: smog, decreased visibility Indirect effect: acid rain, damage to historic landmarks

Introduction Ambient organic aerosol –Heterogeneous composition –Secondary reactions occur in particle Off-line filter sampling –Longer analysis times –Allows secondary reactions to occur to a greater extent Mass spectrometry –Real-time analysis –Structural information –Range of compounds

Mass Spectrometry for Aerosol Analysis Real time analysis –Ambient sampling –MS n capabilities –Transportability Quadrupole ion trap –Compact –High sensitivity –High MS/MS efficiency

Py-LTPI Ionization Method

Experimental Bruker Esquire mg sample pyrolyzed 5 minute equilibration prior to analysis ~2 minutes to reach maximum temperature Spectra averaged over the course of pyrolysis

Cellulose and Lignin Natural polymers Primary components of cell wall Contain mostly carbon, hydrogen, and oxygen Cellulose Lignin

Py-LTPI of Cellulose Intensity x m/z Mass-to-charge ratios can be compared to previously identified compounds Positive Ion Detection Mode Negative Ion Detection Mode Intensity m/z

Previously Identified Compounds in Cellulose 3,5-dihydroxy-2-methyl-4H-pyran-4-one 142 Da 5-hydroxymethyl-furfural 126 Da Furfural 96 Da Levoglucosenone 126 Da Levoglucosan 162 Da 2-methyl-3-hydroxy-4-pyrone 126 Da Syringaldehyde 182 Da 4-ethylsringol 182 Da 2,6-dimethoxyphenol 154 Da Some previously identified compounds have the same mass and will have the same mass-to-charge ratios.

Tandem Mass Spectrometry (MS/MS) Used to differentiate between ions of the same mass-to-charge ratio Ions are subjected to collision- induced dissociation (CID) –Ions dissociate into product ions –Ions can be differentiated by dissociation patterns

3-Hydroxy-2-Methyl-4-Pyrone Standard Intensity m/z Cellulose Aerosol Product MS/MS of 127 Da Only two common fragment ions and the relative intensities for 127 and 109 are dissimilar. Unlikely a compound in cellulose aerosol.

Intensity x m/z 2,6-Dimethoxyphenol Standard Cellulose Aerosol Product MS/MS of 155 Da All fragment ions of 2,6-Dimethoxyphenol match fragment ions of cellulose aerosol. 2,6-Dimethoxyphenol could be a compound in cellulose aerosol.

Cellulose Summary MS/MS by CID allows for comparison of cellulose aerosol product to standards Some peaks match those of standards and could be found in aerosol product Some peaks do not match previously identified compounds

Py-LTPI of Lignin Intensity x m/z Positive Ion Detection Mode Negative Ion Detection Mode Intensity m/z Can the same previously identified compounds from be found in lignin?

Intensity x m/z 2,6-Dimethoxyphenol Standard Lignin Aerosol Product MS/MS of 155 Da Intensity m/z Not all of the fragment ions of standard match the aerosol product and the relative intensities of fragment ion 127 are dissimilar. Unlikely a compound in lignin aerosol.

MS/MS of 127 Da 3-Hydroxy-2-Methyl-4-Pyrone Standard Lignin Aerosol Product Intensity m/z 71 At the same CID voltage, the standard and aerosol product yield different relative intensities for ions 127 and 109. Unlikely a compound in pyrolyzed lignin aerosol.

Unexpected Losses Intensity m/z Intensity m/z 172 Parent ion: 157; Net loss of 10; possible loss of 28 and gain of 18 Loss of 15; possible loss of a methyl radical

Conclusions Some previously identified standards match well with the cellulose aerosol product The same standards do not match well with ions in lignin aerosol product Unexpected losses of 15 Da and 10 Da

Future Work Further investigation of cellulose and lignin aerosol products –Comparison of previous identified compounds in negative mode –Comparison of other cellulose and lignin standards Investigation of cellulose and lignin using Pyrolysis Extractive Electrospray Ionization (Py-EESI)

References 1. Evans, R. J., Milne, T. A. Molecular Characterization of the Pyrolysis Biomass. 1. Fundamentals. Energ Fuel, 1987, 1, Lu, Q., Yang, X.-C., Dong, C.-Q., Zhang, Z.-F., Zhang, X.-M., Zhu, X.-F. Influence of pyrolysis temperature and time on the cellulose fast pyrolysis products: Analytical Py=GC/MS study. J Anal App Pyrol, 2011, 92,

Acknowledgements Thank you to R. J. Reynolds for funding this project Glish Group