MALDImatrixInfo wiki work1. Introduction
Solid state diffuse refractance measurements of 6-aza-2-thiothymine (ATT), 2-amino-4methyl-5-nitropyridine (ANP) and 4-nitroaniline (4-NA) in tetrahydrofurane (THF), methanol
(MeOH) and acetonitrile (CH3CN)
Solid state refractance measurements of three matrices was performed with the utility
of UV/VIS spectroscopy. Three different solvents were used to learn whether the
crystallization from a different solvent has an effect on the solid state absorbance of the
specific matrix. The structures of the three matrices studied are shown in Table 1.
Table 1. Structures of the three matrices studied.
IUPAC Name
6-methyl-3-thioxo-2H-1,2,4-triazin-5-one,
ATT
4-methyl-5-nitro-pyridin-2-amine,
ANP
4-nitroaniline,
4-NA
Structure
2. Experimental
2.1.
Materials
Three matrices 6-aza-2-thiothymine (ATT, PN: 275514 lot #: 04415PD), 2-amino-4
methyl-5-nitropyridine (ANP, PN: 290092 lot #: 02022CA) and 4-nitroaniline (4-NA, PN:
185310 lot #: 03518EH) were purchased from Sigma-Aldrich, St.Louis, MO.
Tetrahydrofurane (THF, CAS: 109-99-9, Lot # 16266PD), methanol (MeOH Chromasolv
Plus for HPLC, CAS: 67-56-1) were purchased from Sigma-Aldrich and acetonitrile (CH3CN
HPLC grade, CAS: 75-05-8, Lot # 965955) was purchased from FisherChemicals…..
Fused silica microscope slides (S1-UV) were purchased from Esco Products, Inc.
2.2.
Sample preparation
6-Aza-2-thiothymine sample solution was prepared by dissolving a solid matrix in 300
µL volume of THF to obtain saturated solution. The solution was prepared at room
temperature in glass Fisherbrand*, class A clear borosilicate glass vials (GPI 8-425 thread;
Capacity, 1/2 dr. (1.8mL); 12 x 35mm) purchased from Fisher Scientific, (Pittsburgh, PA). It
was vortexed for approximately 10 minutes and left overnight. The solution was then
vortexed for another 10 minutes again to ensure that the excess of the solid matrix is still in
the solution. Such solution was centrifuged for 14 minutes at 5000 rpm. The supernatant was
deposited on the microscope slide and solvent allowed to evaporate. UV/VIS measurements
were performed on the solid sample spot.
The remaining matrices were prepared accordingly in THF, MeOH and CH3CN.
2.3.
Instrumentation
Eppendorf AG Centrifuge 5418 (Hamburg) was used to centrifuge the saturated matrix
solutions. Saturated solutions were mixed on a FIsherScientific Vortex Genie 2. All the
spectrophotometric measurements were performed on Perkin-Elmer, Inc. (Shelton, CT)
Lambda-950 UV/Visible Absorption Spectrophotometer.
2.4. Data Analysis
UV/VIS spectra were acquired with a PerkinElmer UV WinLab 5.1.5.0637 software.
Absorption scan was performed from 200 nm to 800 nm wavelength.
3.
Results and Discussion
Solid State Absorbance-microscope slide
0.18
0.16
Absorbance
0.14
0.12
0.1
0.08
fused silica
0.06
0.04
0.02
0
150
350
550
Wavelength [nm ]
750
950
Spectralon disc
0.004
Absorbance
0.003
0.002
0.001
0
-0.001
Series1
0
200
400
600
800
1000
-0.002
-0.003
Wavelength [nm]
Solid State
4-NA in CH3CN
Absorbance
0.9
0.8
0.7
0.6
0.5
0.4
4-NA CH3CN
0.3
0.2
0.1
0
180
380
580
Wavelength [nm]
780
980
Solid State
4-NA in THF
1.4
Absorbance
1.2
1
0.8
4-NA in THF
0.6
0.4
0.2
0
180
380
580
780
980
Wavelength [nm]
Solid State
4-NA in MeOH
0.6
Absorbance
0.5
0.4
0.3
4-NA in MeOH
0.2
0.1
0
180
380
580
780
Wavelength [nm]
980
Absorbance
Solid State
ATT in CH3CN
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
180
ATT in CH3CN
380
580
780
980
Wavelength [nm]
Solid State
ATT in THF
0.8
0.7
Absorbance
0.6
0.5
0.4
ATT in THF
0.3
0.2
0.1
0
180
380
580
Wavelength [nm]
780
980
Solid State
ATT in MeOH
0.8
0.7
Absorbance
0.6
0.5
0.4
ATT in MeOH
0.3
0.2
0.1
0
180
380
580
780
980
Wavelength [nm]
Solid State
ANP in CH3CN
0.7
Absorbance
0.6
0.5
0.4
ANP in CH3CN
0.3
0.2
0.1
0
180
380
580
780
980
Wavelength [nm]
Absorbance
Solid State
ANP in THF
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
180
ANP in THF
380
580
780
Wavelength [nm]
980