346
O. Berdeaux et al. / Chemistry and Physics of Lipids 165 (2012) 338–347
Table 9
Mass spectra ions of short-chain fatty acids.
Compounds
Peak
Main fragmentation ions, m/z
(relative abundance %)
Other fragments, m/z (relative abundance %)
M+
M-29
Hexanoic acid
Heptanoic acid
Octanoic acid
Nonanoic acid
Decanoic acid
21
25
29
33
37
116(1.6)
130 (tr)
144 (3)
158 (3)
87(14.5) 73 (49), 60 (100), 55 (13), 45 (16), 43 (19), 41 (28), 29 (12)
101 (7)
87 (25), 73 (57), 60 (100), 55 (29), 45 (20), 43 (22), 41 (28), 29 (12)
115 (12)
129 (31)
143 (10)
101 (27), 84 (62), 73 (80), 60 (100), 55 (57), 45 (15), 43 (68), 41 (50), 29 (20)
115 (35), 98 (19), 87 (16), 73 (93), 60 (100), 55 (38), 45 (19), 43 (38), 41 (44), 29 (45)
129 (53), 115 (20), 101 (11), 87 (33), 73 (100), 60 (85), 55 (58), 45 (20), 43 (31), 41 (58), 29 (23)
172 (12)
tr, traces (0.1).
Table 10
Mass spectra ions of volatile aldehydes and alcohols.
Compounds
Peak
Main fragmentation ions,
Other fragments, m/z (relative abundance %)
m/z (relative abundance %)
M+
M-18
Hexanal
Octanal
Nonanal
Decanal
(E)-hept-2-enal
(E)-oct-2-enal
(E)-non-2-enal
2-Decenal
(E)-undec-2-enal
(E,Z)-deca-2,4-dienal
(E,E)-deca-2,4-dienal
Pentan-1-ol
Octan-1-ol
1
5
8
12
6
9
13
16
18
19
20
3
100 (0.6)
128(0.7)
142 (0.3)
156 (ND)
112 (6)
126 (tr)
140 (tr)
154 (0.6)
168(0.1)
152 (8)
82 (23)
110 (10)
124(3.5)
128 (14)
94 (9)
108 (9)
122 (9)
136 (4)
150 (3)
134 (1)
134(0.2)
70 (64)
112 (1.4)
72 (28), 67 (16), 56 (100), 44 (99), 41 (94), 39 (39), 29 (47)
100 (12), 84 (66), 69 (39), 57 (77), 43 (100), 41 (86), 39 (34), 29 (50)
114(9.5), 98 (36), 82 (35), 70 (34), 57 (100), 43 (57), 41 (72), 39 (24), 29 (43)
112 (40), 96 (45), 82 (63), 70 (57), 57 (100), 43 (79), 41 (90), 39 (22), 29 (27)
97(14.5), 83 (99), 70 (53), 55 (88), 41 (100), 39 (54), 29 (34)
97 (24), 83 (62), 70 (89), 55 (100), 41 (90), 39 (46), 29 (36)
111 (18), 96 (37), 83 (89), 70 (93), 55 (89), 43 (100), 41 (79), 39 (52), 29 (41)
125 (3),121 (9), 110 (18), 98 (28), 83 (66), 70 (100), 55 (91), 43 (88), 41 (87), 39 (41), 29 (37)
139 (2), 135 (2), 121 (22), 111 (15), 97 (25), 83 (67), 70 (100), 57 (84), 55 (74), 41 (95), 39 (34), 29 (39)
137 (3), 123 (9), 109 (3), 95 (16), 81 (100), 67 (24), 55 (26), 41 (30), 39 (16), 29 (12)
123 (3), 109 (2), 95 (10), 81 (100), 67 (15), 55 (10), 41 (20), 39 (11), 29 (9)
55 (79), 42 (100), 31 (36), 29 (36)
152 (8)
88 (ND)
130 (ND)
15
97 (7), 84 (44), 70 (64), 56 (100), 43 (58), 41 (79), 29 (46)
ND, not detected; tr, traces (<0.1).
alkyl group as a free radical, leaving CO2H+. Moreover, the most
abundant peaks were often found at m/z = 60, which can be
attributed to the McLafferty rearrangement ion, and at m/z 73 in the
lower molecular weight range. The presence of ions at m/z 60 and
45 is indicative of carboxylic acids. In addition for longer saturated
fatty acid like decanoic acid, the mass spectrum showed ions from
m/z = 115 to 155 representing fragmentations between methylene
groups of the form [HOOC(CH2)n]+.
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