Table 2. Summary of the Major Ionic Fragments of Electrosprayed [CMA-H]−, [CA-H]−, and [FA-H]− Produced upon Higher-Energy Collisional Dissociation (HCD) and UV–Vis Laser Photoexcitation at ca. 2.95 and 4.75 eV.
| obsd in
laser photoexcitation (from EtOH ESI)b |
obsd in laser photoexcitation (from MeCN ESI)b |
||||||
|---|---|---|---|---|---|---|---|
| ionic fragmentm/za | accompanying neutral fragment | obsd in HCDb | 2.95 eV | 4.75 eV | 2.95 eV | 4.75 eV | |
| [CMA-H]− (m/z 163) | 119 | CO2 | √ (vs) | √ (vs) | √ (vw) | √ (vs) | √ (vw) |
| [CA-H]− (m/z179) | 135 | CO2 | √ (s) | √ (vs) | √ (vw) | √ (vs) | √ (vw) |
| 134 | CO2 + H• | √ (w) | √ (w) | √ (w) | |||
| [FA-H]− (m/z193) | 178 | CH3• | √ (m) | √ (w) | √ (vw) | √ (m) | √ (vw) |
| 149 | CO2 | √ (w) | √ (m) | √ (s) | |||
| 134 | CH3• + CO2 | √ (s) | √ (w) | √ (s) | √ (m) | √ (vw) | |
| 117 | √ (vw) | √ (vw) | |||||
a
Determined with mass accuracy >0.3 amu.
b
Very strong (vs), strong (s), medium (m), weak (w), and very weak (vw). Proposed structures are outlined in Table S10.