Peak 3: Unknown. This peak had a molecular ion at m/z 331.1
and product ion at m/z 169.0 (Fig. 3), suggesting it was a molecule
containing gallic acid and hexose moieties. However, it is
important to note that the UV spectra of this peak had two
maximums at 255 and 303 nm, which are quite different from any
known gallic acid derivative. Thus, even the mass spectra data for
this peak suggested it was monogalloyl hexose, more information
should be acquired to establish its structure unambiguously.