Effects of Dissolution of Biomass in Ionic Liquids Using Direct Analysis in Real Time (DART) Mass Spectrometry Casey Howdieshell a, Darrin Smith a, Bruce Pratt b a Eastern Kentucky University, Department of Chemistry, Richmond, KY b EKU Center for Renewable and Alternative Fuel Technologies (CRAFT) This research has been funded in part by the Defense Logistics Agency (DLA) distributed by the Center for Renewable and Alternative Fuel Technologies (CRAFT) as well as the Undergraduate Analytical Research Program from the Society for Analytical Chemists of Pittsburgh (SACP). Biomass has become progressively important in recent years. Through pretreatment and saccharification processes, sugars produced from switchgrass can be used by algae to result in biofuel production. For these processes to occur, cellulose must be separated from hemicellulose and lignin components of the biomass. A major obstacle in biofuel development is removal of lignin, an organic polymer that contributes to plant cell wall stability. Ionic liquids are low-temperature molten salts that possess chemical and physical properties which aide in dissolution of whole biomass. This study focuses on the interactions of quiescent switchgrass (Panicum vigatum) with ten different ionic liquids. These interactions were tested using microscopic techniques as well as Direct Analysis in Real Time (DART) mass spectrometry. Results from these studies show the effectiveness and parameters for separation of biomass components. Effective separation will potentially lead to a better biofuel yield as well as potential for commercial scale production. Quiescent switchgrass (Panicum vigatum) was mowed, windrowed, and bailed. Whole biomass was extracted with a hay probe and ground up. Lignin was extracted from switchgrass using formic acid at T= 25 o C, 50 o C, and 75 o C. Ionic Liquids used include: [AMIM][Cl], [AMIM][XS], [BMIM][Cl], [BMIM][XS], [PMIM][Br], [PMIM][NO 3 ], [PMIM][Sulfone], [THTDP][Br], [THTDP][NO 3 ], [THTDP][NH 2 ]. Optical Microscope: Leica DM EP using 40x Magnification Different biomass samples and ionic liquids were combined on a microscope slide. Masses of both biomass and ionic liquid were recorded. Immediate observation using microscope to see if dissolution occurred within 30 minutes. Dissolution was recorded at 5 minute intervals using cell-phone camera (8 mega pixel). Samples were transferred micro-vials and observed after t = 24 hr. Each combination was characterized as either noticeable dissolution at 30 min, noticeable dissolution at 24 hr, partial dissolution after 24 hr, or no dissolution at all. Instrumentation: Thermo Scientific LTQ XL with DART SVP Ion Source. Samples from microscopy experiments were coated onto glass Dip-It tips and introduced to ion source. Mass spectra were obtained for each ionic liquid in both (+) and (-) mode. Figure 1. Lignin extract dissolution in [BMIM][Cl] at t = 0 min Figure 3. Lignin extract dissolution in [BMIM][Cl] at t = 24 hr Figure 6. DART positive (+) ion mass spectrum generated with lignin extract (50 o C FA) after dissolution with [BMIM][Cl]. Figure 5. DART-SVP Ion Source Figure 2. Lignin extract dissolution in [BMIM][Cl] at t = 30 min [AMIM][Cl] and [BMIM][Cl] yielded notable dissolution at 30 min. [PMIM][NO 3 ], [AMIM][XS], [BMIM][XS], [PMIM][Br] all showed no visible dissolution at 30 min, but after 24 hr dissolved lignin completely. [BMIM][XS], [THTDP][Br], and [THTDP][NO 3 ] all showed partial dissolution after 24 hr. [PMIM][Sulfone] and [ThTDP][NH 2 ] showed no dissolution at any time. From a previous study, the m/z for prominent ionic liquid fragmentations 1 are shown in spectra ( ) as expected. Reoccurring 174 m/z loss indicates solvent. Unknown peaks are also present ( ), suggesting the presence of lignin fragment adducts. Reoccurring 148 and 198 m/z loss may suggest lignin monomers. Future directions include: Continued observation of ionic liquid as solvents for all biomass samples. Collection of mass spectra from each combination (140 total). This includes (+) and (-) mode scans. Assigning m/z with known lignin fragments for each combination. Determining, if efficient combination is found, how resulting saccharification process is affected via sugar analysis. Upscale dissolution analysis to larger quantities. 1.M. Mazzotta, R. Pace, B. Wallgren, S. Morton III, K. Miller, D. L. Smith, “Direct Analysis in Real Time Mass Spectrometry (DART-MS) of Ionic Liquids”, J. Am. Soc. Mass Spectrom., 2013, 24 (10), Figure 4. [BMIM][Cl] Structure