Table 1.
MS/MS fragmentation of CA derivatized amino acids, neurotransmitters and isobaric analogs
| Compounda | [M + H]+ | MS/MS Fragments, m/zb | MS3 Fragment, m/z |
|---|---|---|---|
| Dopamine | 314 | 137, 178, 190, 259 | |
| 4-hydroxy-3-methoxybenzylamine | 137, 178 | ||
| Norepinephrine | 330 | 161, 188, 312 | 152c |
| 5-hydroxydopamine | 153, 178, 206, 275 | ||
| 6-hydroxydopamine | 151, 153, 178, 275 | ||
| Epinephrine | 344 | 137, 166, 190, 208 | |
| dl-normetanephrine | 175, 202, 326 | ||
| GABA | 264 | 161, 178, 191, 209 | 191d |
| dl-2-aminobutyric acid | 161, 218 | ||
| 2-aminoisobutyric acid | 161,218 | ||
| dl-3-aminoisobutyric acid | 161, 190, 209, 246 | 153d | |
| N-ethylglycine | 151, 161, 181 | ||
| N-methyl-L-alanine | 128, 137, 161 | ||
| Tryptophan | 365 | 178, 236, 272, 348 | |
| Tyrosine | 342 | 161, 165, 342182, 296 | |
| Glutamic acid | 308 | 148, 161, 262, 290 | |
| Serotonin | 337 | 160, 178, 228, 282, 294, 308, 320 | |
| Melatonin | 393 | 233, 243, 269, 334 |
a
Derivatized (with 4-hydroxy-3-methoxycinnamaldehyde) amino acid or neurotransmitter is underlined with its isobaric analog listed below
b
Target amino acid or neurotransmitter fragment mass highlighted in bold if used for ion image reconstruction
c
Transition used for norepinephrine-CA (m/z 330→312→152) ion image reconstruction
d
Fragment mass used for confirmation of identity (m/z 264→209→)