precursor ion in the Q1 and study the fragments obtained in
the collision cell by a full scan in the Q3. The collision energy
for each transition must be optimized.
4. The use of the proton adduct as the precursor ion is always
recommended (when it is produced), even if the sodium
adduct is more intense, for two reasons. Firstly, the identification of the SL is improved and on the other hand the sodium
adduct are normally more stable being the energy required for
the fragmentation higher.
5. SLs fragments expected could be summarized as follow: Firstly,
the loss of a water molecule (À18) or the loss of an acetate
group (À59), when a hydroxyl or an acetate group is present in
the structure, and then the loss of the D-ring moiety (À97)
(Fig. 3).
6. Ambar vials are recommended to preserve SLs of the light
degradation.
7. Set the autosampler with a temperature as lower than possible
to preserve the samples.
Acknowledgments
This research was supported by the Ministerio de Economı ´a, Industria y Competitividad (MINEICO) (Project AGL2017-88-083-R).
Fig. 3 Fragmentation pattern of SLs
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