HPLC-DAD-MS/MS Analysis of Authentic Compounds.
To identify structures of the constituents in the peels of STJ,
eight reference compounds were analyzed by HPLC-DAD-ESIMS/
MS techniques. According to their chemical structures, UV
absorption maxima, and dominant fragmentation pathways, the
authentic compounds could be classified into three groups
including polymethoxylated flavones, flavanones, and chalcones.
In their full scan mass spectra, most of PMF standards exhibited
[M + H]+ ions of sufficient abundance that could be
subsequently isolated automatically and subjected to CIDMS/
MS analysis (shown in Table 1). The proposed
fragmentation patterns were helpful to clarify the structural
identification of constituents in the peels of STJ. The
nomenclature commonly used for mass fragments of flavonoids
was adopted in this work