Supplement material
to
Ref. JASMS Ms. No. 2012-5464
Detection of an amine impurity and quality assessment related
to this impurity of the UV MALDI matrix -cyano-4-hydroxycinnamic acid for the analysis of peptides in the attomole
range
Justyna Rechthaler, Ernst Pittenauer, Tanner M. Schaub and
Günter Allmaier
Legends to Figures in the Supplement
Figure 1S Positive-ion MALDI mass spectra (curved field reflectron mode) of two CHCA matrix
batches: matrix B (a) and matrix E (b). Matrix solvent: acetone. The mass spectrum (a) exhibits a
[M+H]+/[M*+H]+ ratio > 1, which represents a high quality matrix, and the following spectrum (b) a
[M+H]+/[M*+H]+ ratio < 1 representing a matrix of lower quality.
Figure 2S Comparison of the [M+H]+/[M*+H]+ (a) and [2M+H]+/[M*+H]+ (b) ratios of five various
CHCA matrix batches (A, B, C, D and E, matrix solvent: acetone) obtained on a bench-top (MALDI IV)
and floor-standing high resolution TOF instrument (AXIMA-CFR).
Figure 3S Positive-ion MALDI FT-ICR mass spectrum of the matrix E (including highest amount of the
contaminant) with the region around m/z 102. The spectrum was internally calibrated with following
matrix signals: [M-CO2+H]+, [M-H2O+H]+ and [M+H]+. The RMS error on the three point calibration
was -1.22 ppm. The mass spectrometric resolving power observed for the m/z 102.1276 signal was
230000 (FWHM).
Figure 4S Positive-ion MALDI high energy (ELab 2 keV) CID (LinTOF/RTOF) mass spectrum of the
precursor ion m/z 102.2 (derived from matrix E in acetone).
Fig. 1S a
[M+H]+
%Int.
190
100
90
[M-H2O+H]+
80
172
70
60
50
[M*+H]+
40
280
102
30
[M-CO2+Na]+
168
20
[2M+H]+
[M+Na]+
212
379
10
0
100
120
140
160
180
200
220
240
260
Mass/Charge
280
300
320
340
360
380 400
Fig. 1S b
%Int.
[M*+H]+
102
100
90
80
70
60
50
40
[M-CO2+Na]+
[M+H]+
172 190
30
20
[M+Na]+
[2M+H]+
379
212
10
0
100
120
140
160
180
200
220
240
260
Mass/Charge
280
300
320
340
360
380 400
Fig. 2S a
MALDI IV
AXIMA CFR
9
8
6
5
+
[M+H] /[M*+H]
+
7
4
3
2
1
0
A
B
C
CHCA matrices
D
E
Fig. 2S b
MALDI IV
AXIMA CFR
3,5
2,5
2
+
[2M+H] /[M*+H]
+
3
1,5
1
0,5
0
A
B
C
CHCA matrices
D
E
Fig. 3S
[M*+H]+
102.1276
12C H N
6 16 1
observed at m/z: 102.1276
Theoretical mass at m/z: 102.12772
Error: –1.2ppm
102.1
102.2
102.3
102.4
m/z
Fig. 4S
+N
600
58.14
CH3
CH3
Precursor ion
C6H16N
[M*+H]+
CH3
CH2
CH3
+N
CH3
CH3
CH
+N
CH3
H CH
2
+NH
CH3
CH2
CH2
CH2
CH3
Intensity
+N
CH3
CH3
CH3
+
H
NH CH3
CH2
CH3
+NH
CH3
CH3
0
20
30
CH3
72.16
CH2
40
CH3
59.14
73.17
74.18
CH2
60
50
m/z
102.20
60.16
44.11
+HN
CH2
70
80
90
100
CH3