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. Author manuscript; available in PMC: 2010 Jul 12.
Published in final edited form as: J Pharm Biomed Anal. 2009 Feb 20;49(5):1141–1149. doi: 10.1016/j.jpba.2009.02.011

Table 2.

Fragments formed by collisionally induced dissociation (MS-MS) of the MH+ ion of various E. purpurea alkylamides.

Designation, name, m/z group i4 group ii5 group iii6 group iv7 group v8
RI3 30–90% RI 30–90% RI 60–100% RI 26–100% RI < 3–20%
D
2441 		Undeca-2E,4Z-diene-8,10- diynoic acid 2-metylbutyl amide 157 129 131 174 188,202, 216
E
244		 Undeca-2Z,4E-diene-8,10- diynoic acid 2- methylbutylamide2 157 129 131 174 188,202, 216
F
244		 Dodeca-2Z,4E-diene-8,10- diynoic acid isobutylamide 171 143 145 188 202, 216
G
244		 Dodeca-2E,4Z-diene-8,10- diynoic acid isobutylamide 171 143 145 188 202, 216
P
258		 Trideca-2Z,7E-diene-8,10- diynoic acid isobutylamide 185 157 159 202 216,230
Q
258		 Dodeca-2E,4Z-diene-8,10- diynoic acid 2- methylbutylamide 171 143 145 188 202, 216
1

The number beneath the letter designation indicates the m/z value for the MH+ ion.

2

Proposed structure for compound E based on retention time and MS/MS fragmentation.

3

RI corresponds to relative Intensity.

4

The group i fragments correspond to acyllium ions as shown in Figure 2

5

The group ii fragments are carbocations that correspond to the alkyl chain of the alkylamide and are formed by loss of the amide portion (isobutylamide or 2-methylbutylamide).

6

The group iii fragments correspond to the alkyl chain of the alkylamide and are formed by the loss of the amide portion of the molecule and saturation of one of the double bonds on the akyl chain.

7

The group iv fragments correspond to the protonated alkylamide minus the N-alky group

8

The group v fragments correspond to the protonated alkylamide minus various portions of the N-alkyl group (see Figure 2).