Supplementary Material
Internal Energy Deposition for Low Energy, Femtosecond Laser Vaporization
and Nanospray Post-ionization Mass Spectrometry using Thermometer Ions
Paul M. Flanigan IV,1,2 Fengjian Shi,1,2 Jieutonne J. Archer, 1,2 Robert J. Levis1,2*
1
2
Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, PA, 19122
Center for Advanced Photonics Research, Temple University, 1901 N. 13th St., Philadelphia,
PA, 19122
*Contact Information for Corresponding Author:
Email: rjlevis@temple.edu
-1-
Figure S1. Nanospray-MS/MS mass spectra of the p-MeO benzylpyridinium ion from a buffered
solvent. The M+ (left) and M+-pyridine (right) features, highlighted with the blue
squares, were isolated in the collision cell and fragmented using the CID energy shown
on the right. The ISCID voltage was adjusted to enable significant intensity of the M+pyridine feature for isolation and fragmentation in the plot on the right.
-2-
Figure S2. Nanospray-MS/MS mass spectra of the p-Me benzylpyridinium ion from a buffered
solvent. The M+ (left) and M+-pyridine (right) features, highlighted with the blue
squares, were isolated in the collision cell and fragmented using the CID energy shown
on the right. The ISCID voltage was adjusted to enable significant intensity of the M+pyridine feature for isolation and fragmentation in the plot on the right.
-3-
Figure S3. Nanospray-MS/MS mass spectra of the p-Cl benzylpyridinium ion from a buffered
solvent. The M+ (left) and M+-pyridine (right) features, highlighted with the blue
squares, were isolated in the collision cell and fragmented using the CID energy shown
on the right. The ISCID voltage was adjusted to enable significant intensity of the M+pyridine feature for isolation and fragmentation in the plot on the right.
-4-
Figure S4. Nanospray-MS/MS mass spectra of the p-NO2 benzylpyridinium ion from a buffered
solvent. The M+ (left) and M+-pyridine (right) features, highlighted with the blue
squares, were isolated in the collision cell and fragmented using the CID energy shown
on the right. The ISCID voltage was adjusted to enable significant intensity of the M+pyridine feature for isolation and fragmentation in the plot on the right.
-5-
Analyte
M+
(m/z)
M+ - Pyridine
(m/z)
p-MeO
200.3
121.2
p-Me
184.3
105.2
p-Cl
204.7
125.6
p-NO2
215.2
136.1
Other Fragments Observed by Nanospray
Tandem MS using Bruker MicrOTOF-Q II
(m/z)
53, 55, 60, 65, 66, 69, 73, 77,a 78, 80,b 81, 89, 91,a
93, 95, 105, 106,a 107, 109, 111, 137,d 157,b 165,
170,b 183,c 184, 199
51, 53, 59, 60, 63, 64.5, 65, 71, 73, 74, 77,a 78, 79,a
80, 81, 89, 91, 93, 95, 103,a 123, 151, 157,b 164,
165, 167, 169, 170b
63, 65, 69, 73, 75, 80,b 81, 89,a 90, 91, 99,a 101, 123,
133,d 151,d 155, 157,b 163,d 169,d 170,b 174,d 187,
190,b 192d
52, 63, 78,a 79, 80,b 81, 89,a 90, 91, 99, 105, 106,a
107, 117, 122, 123, 133,d 157,b 165,d 169,a 170
M+: molecular ion
Bold: Other fragment features observed in nanospray and LEMS analyses with buffered solvent
a
: Features also observed in [37]
b
: Features observed in nanoESI and LEMS analyses but not observed during tandem MS experiments
c
: Features excluded due to large mass spectral background
d
: Features observed in tandem MS with acidic solvent but not with buffered solvent
Table S1. Fragments observed in the analysis of benzylpyridinium ions with a buffered solvent
using conventional nanospray-MS and less energetic femtosecond laser vaporization
with nanospray postionization.
-6-
Figure S5. Blank-subtracted mass spectra for the p-MeO benzylpyridinium ion using 800 nm laser
pulses with varying pulse energies for vaporization into an ammonium acetate buffered
nanospray solvent. Benzylpyridinium ions were mass analyzed using a collision cell
voltage of 10 eV. The condensed phase of benzylpyridinium ion, liquid or dried, and
the laser pulse energy are labeled for each experiment. The M+ and M+-pyridine
features are denoted by the blue squares and red circles, respectively.
-7-
Figure S6. Blank-subtracted mass spectra for the p-Me benzylpyridinium ion using 800 nm laser
pulses with varying pulse energies for vaporization into an ammonium acetate buffered
nanospray solvent. Benzylpyridinium ions were mass analyzed using a collision cell
voltage of 10 eV. The condensed phase of benzylpyridinium ion, liquid or dried, and
the laser pulse energy are labeled for each experiment. The M+ and M+-pyridine
features are denoted by the blue squares and red circles, respectively.
-8-
Figure S7. Blank-subtracted mass spectra for the p-Cl benzylpyridinium ion using 800 nm laser
pulses with varying pulse energies for vaporization into an ammonium acetate buffered
nanospray solvent. Benzylpyridinium ions were mass analyzed using a collision cell
voltage of 10 eV. The condensed phase of benzylpyridinium ion, liquid or dried, and
the laser pulse energy are labeled for each experiment. The M+ and M+-pyridine
features are denoted by the blue squares and red circles, respectively.
-9-
Figure S8. Blank-subtracted mass spectra for the p-NO2 benzylpyridinium ion using 800 nm laser
pulses with varying pulse energies for vaporization into an ammonium acetate buffered
nanospray solvent. Benzylpyridinium ions were mass analyzed using collision cell
voltage of 10 eV. The condensed phase of benzylpyridinium ion, liquid or dried, and
the laser pulse energy are labeled for each experiment. The M+ and M+-pyridine
features are denoted by the blue squares and red circles, respectively.
- 10 -
Figure S9. UV-visible absorption profiles for the p-substituted benzylpyridinium ions. The
concentrations were 1 mM in 1:1 (v:v) methanol:water for every thermometer ion. All
UV-Vis spectra were achieved using an Ultrospec 2100 pro UV-Vis spectrometer (GE
Healthcare Biosciences, Pittsburgh, PA).
- 11 -
Figure S10. Mass spectrum showing background features from the nanospray of the ammonium
acetate buffer on the high resolution mass spectrometer.
- 12 -
Figure S11. Comparison of internal energy deposition of LEMS using 800 nm laser pulses with
varying pulse energies for vaporization of dried BzPy ions into an ammonium acetate
buffered nanospray solvent. Survival yield values were plotted as a function of
critical energy, Eo, at a collision cell energy of 10 eV. The derivatives of the sigmoidal
curves produced the internal energy distributions (P(E)), as shown in the bottom plot.
The sigmoidal fit R2, <Eint>, and FWHM values for each technique are shown. Since
there was no kinetic shift correction, these calculated <Eint> values only indicate
relative energies. Due to the poor R2 values, the sigmoidal model is unsuitable to
accurately calculate <Eint> for 800 nm dried LEMS using these BzPy salts.
- 13 -