Abstract: A method for the determination of quercetin in pulp and peel of apples by reversed-phase high performance liquid chromatography with internal standard was developed. Samples were frozen at -80 ℃ for 24 h, then added 6 mol/L hydrochloride under the protection of antioxidant 2,6-di-tert-butyl-p-cresol. The slurry was hydrolyzed thermostatically at 90 ℃ for 2 h and centrifugated for 10 min. The separation was performed on an ODS column (150 mm×6.0 mm i.d., 5 μm). Methanol-water (55∶45, v/v) (pH adjusted to 3.3 with acetic acid) was used as the mobile phase with a flow rate of 1.0 mL/min. The injection volume was 20 μL. The detection wavelength was 370 nm. The results showed that the quercetin content in pulp and in peel were 3.11-10.78 μg/g and 253.57-744.59 μg/g, respectively. The mean recovery of quercetin in apple pulp was 100.4%. The method is simple, accurate, and reliable.

Key words: apple , quercetin, reversed-phase high performance liquid chromatography