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·1154· 精细化工 FINE CHEMICALS 第 36 卷

group information of the compounds [26,27] . The FTIR
spectrum of FMTs after purification is shown in Fig.5.
The wide and strong band at approximately 3431.09
–1
cm indicated the primary adsorption of the associated
–1
phenolic hydroxyl of FMTs (3500~3000 cm ). The
−1
peak at 2919.99 cm was attributed to the stretching
vibration of aliphatic and aromatic C—H groups
−1
(2950~2850 cm ). The adsorption peak at approximately
–1
1625.86 cm may be due to the C==O stretching
–1
vibration (1690~1620 cm ). Due to the stretching
vibration of C==C in the benzene ring, there were
continuous absorption peaks at approximately
–1
–1
–1
1515.93 cm , 1456.14 cm and 1363.56 cm (1600~
–1
–1
1450 cm ). Specifically, 1261.34 cm , 1203.48 cm –1
–1
and 1170.60 cm are continuous peaks that may be
caused by the stretching vibration of C—O groups in
–1
the benzene ring (1260~1000 cm ). The absorption
–1
–1
peaks of 1072.34 cm and 1031.83 cm may be due

Fig. 3 Dynamic leakage curves of FMTs in the column
with the AB-8 resin (A); dynamic desorption
curves of FMTs using different ethanol
concentrations at a rate of 2 BV/h(B)

3.7 Dynamic desorption of AB-8 resin
Ethanol is the most common desorption solution
because it is easily recovered and lacks toxicity. The
ethanol concentration is one of the most important
factors in the dynamic desorption process of adsorbates
from the resins [24,25] . Here, different concentrations of
ethanol solution were used for the dynamic desorption
of FMTs at a flow rate of 2 BV/h. After the adsorption,
the fully saturated column was washed with distilled
water (6 BV) and subsequently flushed with 20%
(6 BV), 40% (6 BV), 60% (6 BV) and 80% (6 BV)
ethanol in water (volume fraction). As shown in
Fig.3B, for FMTs, 20% ethanol (volume fraction) was
the best eluent. When the ethanol concentration was

30%, more impurities were desorbed. Hence, 6 BV of Fig. 4 Chromatograms of the extracts of Malus toringoides
20% ethanol was selected as the desorption solution (Rehd.) Hughes leaves (A) and the product separated
for a high yield. The flavonoids were obtained from by the AB-8 resin (B).
the eluate of 20% (volume fraction) aqueous ethanol
solution by vacuum distillation recovery. The HPLC
chromatograms of FMTs before and after treatment on
AB-8 resin were compared. As described in Fig.4, the
content of total flavonoids in the extracts of Malus
toringoides (Rehd.) Hughes leaves were increased
1.80-fold from 32.79% (mass fraction) to 59.18%
(mass fraction) with a recovery yield of 91.45%.
3.8 FTIR spectrum analysis of FMTs after
purification
An FT-IR spectrum is the absorption spectrum of
molecular motions. The location and shape of the
absorption peaks in the spectrum can infer functional Fig. 5 FTIR spectrum of FMTs after purification