[Determination of 21 polyphenols in fruits by high performance liquid chromatography]

To establish a high performance liquid chromatography(HPLC) method for simultaneous determination of flavonoids(epicatechin, isoorientin, eriocitrin, hyperoside, narirutin, naringin, hesperidin, neohesperidin, quercetin, didymin, naringenin and hesperetin), phenolic acids(gallic acid, chlorogenic acid, caffeic acid, ferulic acid, sinapic acid and p-coumaric acid), terpenoids(limonin), stilbenes(piceatannol and resveratrol) in fruits.

Add ethanol-water(4∶1, V/V) solution to the fruit pulp sample, ultrasonic extraction at 55 ℃ for 10 min, after centrifugation, the supernatant was dried and re-dissolved, and then eluted with ZORBAX Eclipse XDB-C_(18)(4.6 mm×100 mm, 3.5 μm) as chromatographic column, polyphenols are determined by HPLC under switching wavelength, and quantified by external standard method.

The 21 polyphenols can be detected within 45 min and well separated from baseline, with linear correlation coefficients greater than 0.999, the detection limit of the method was 0.03-0.31 μg/g, and the limit of quantitation of the method was 0.09-1.03 μg/g. The intra-day precision was 0.5%-9.3%, the inter-day precision was 2.0%-9.6%. The recoveries of more than 90% polyphenols in the three fruits at three levels were between 80.0% and 119.8%. The relative standard deviation of spiked recoveries of three samples was less than 10.8%. The detection result of citrus, mango, blueberry, persimmon and other samples proved that the composition of polyphenols in different fruits was different.

The method is sensitive, accurate and reproducible, and is suitable for the determination of polyphenols in fruits.