Fig 1.
Chemical structure of VB3 and VB7.
Fig 2.
The synthesis procedure of AEAO.
Fig 3.
The extraction process of tea samples.
Table 1.
Box-Behnken design and observed response.
Fig 4.
Scheme of derivation reaction of AEAO with VitaminB7.
Table 2.
Estimated regression coefficients for the quadratic polynomial model and ANOVA for the experimental results in the optimization of flavonoids extractions.
Fig 5.
The 3D response surface of peak area affected by varying derivatization temperature and time(a), varying derivatization temperature and EDC dosage (b), derivatization time and EDC dosage (c).
Fig 6.
The representative chromatograms for blank (a) spiked blank with standard VB3(b),VB7(c), VB3 and VB7(d), and tea samples (e).
Table 3.
Linear range, correlation coefficient, precision, accuracy, quantitative limits, detection limits and repeatability.
Table 4.
Main content of VB3 and VB7 in the tea.
Table 5.
Comparisons of the proposed method with previously reported methods.