Transcript Slide 1

Effects of Dissolution of Biomass in Ionic Liquids Using
Direct Analysis in Real Time (DART) Mass Spectrometry
a
Howdieshell ,
a
Smith ,
b
Pratt
Casey
Darrin
Bruce
a Eastern Kentucky University, Department of Chemistry, Richmond, KY
b EKU Center for Renewable and Alternative Fuel Technologies (CRAFT)
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= 25oC, 50oC, and 75oC.
• Ionic Liquids used include: [AMIM][Cl], [AMIM][XS], [BMIM][Cl], [BMIM][XS],
[PMIM][Br],
[PMIM][NO3],
[PMIM][Sulfone],
[THTDP][Br],
[THTDP][NO3],
[THTDP][NH2].
Figure 1. Lignin extract
dissolution in [BMIM][Cl]
at t = 0 min
Figure 2. Lignin extract
dissolution in [BMIM][Cl]
at t = 30 min
Figure 3. Lignin extract
dissolution in [BMIM][Cl]
at t = 24 hr
Lignin-IL_3xB1 #24-89 RT: 0.07-0.25 AV: 66 SB: 166 0.00-0.07 , 0.25-0.65 NL: 1.22E4
T: ITMS + p NSI Full ms [50.00-1200.00]
139
100
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.
95
90
85
80
75
83
70
•
•
•
•
Relative Abundance
65
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.
60
Figure 4. [BMIM][Cl]
Structure
55
50
45
40
35
Figure 5. DART-SVP Ion Source
30
25
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), 1616-1619
125
20
314
15
838
10
663
487
5
163 183
0
100
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.
• [AMIM][Cl] and [BMIM][Cl] yielded notable dissolution
at 30 min.
• [PMIM][NO3], [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][NO3] all
showed partial dissolution after 24 hr.
• [PMIM][Sulfone] and [ThTDP][NH2] showed no
dissolution at any time.
• From a previous study, the m/z for prominent ionic
liquid fragmentations1 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.
200
253
453
341
300
400
509
500
577
638
600
m/z
1012
688
700
814
800
864
988
900
1000
1186
1038
1100
1200
Figure 6. DART positive (+) ion mass spectrum generated with lignin extract
(50oC FA) after dissolution with [BMIM][Cl].
www.craft.eku.edu
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).