UPLC-ESI-MS/MS Analysis and Evaluation of Antioxidant Activity of Total Flavonoid Extract from Paeonia lactiflora Seed Peel and Optimization by Response Surface Methodology (RSM)

Figure 2

Response surface plots (a, c, e) and contour plots (b, d, f) of flavonoid yield affected by extraction temperature (), liquid-solid ratio (), and ultrasonic time ().

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