N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
8.13 Spectra of Solvents and References
437
Matrix Compounds in Positive Ionization FAB Mass Spectra
3-Nitrobenzyl alcohol (M r 153.1)
Glycerol (M r 92.1)
1-Thioglycerol (M r 108.2. Note m/z 23, Na + ; 131, [M+Na] + ; 239, [2M+Na] + .
Similarly, small K + impurities give signals at m/z 39, 147, 255)
1,4,7,10,13,16-Hexaoxacyclooctadecane (18-crown-6, M r 264.3. Also used as an
additive; binds metal ions and reduces [M+metal ion] + in favor of [M+H] + , which
can be important for samples with exchangeable H + , such as for peptides [1])
100
50
0
400
350
300
250
200
150
100
50
0
2.0
1.0
0.0
1000
950
900
850
800
750
700
650
600
550
500
5
500
450
400
51
89
136
107
289
154
307
460
596 613
39
77
766
100
50
0
250
200
150
100
50
0
3.0
1.5
0.0
1000
950
900
850
800
750
700
650
600
550
500
10
500
450
400
350
300
250
45
75
57
93
185
277
369
461
553
645
737
829
921
100
50
0
250
200
150
100
50
0
6.0
3.0
0.0
1000
950
900
850
800
750
700
650
600
550
500
500
450
400
350
300
250
45
73
57
91
217
181
325
239
541
199
307
279
165
109
131
23
100
50
0
500
450
400
350
300
250
200
150
100
50
0
2.0
1.0
0.0
1000
950
900
850
800
750
700
650
600
550
500
45
73
133
87
265
177
219
527
31 59
221
789