LAUSR

HighlightsAbout 8 phenolic acids and 14 flavonoids in Chenopodium formosanum are determined by HPLC‐DAD‐MS/MS.A C18 column and gradient solvents 0.1% aqueous formic acid and acetonitrile are used for separation.Quantitation is by two internal standards caffeic acid and kaempferol‐3‐O‐rutinoside.The total content of phenolic acids and flavonoids are 2119.7 and 790.7 &mgr;g/g, respectively.A high recovery and reproducibility was shown for both phenolic acids and flavonoids. ABSTRACT A high performance liquid chromatography‐diode array detection‐tandem mass spectrometry method (HPLC‐DAD‐MS/MS) was developed for simultaneous determination of phenolic acids and flavonoids in djulis (Chenopodium formosanum Koidz.), a traditional Chinese herb reported to possess vital biological activities. A high yield of phenolic acids and flavonoids was attained by employing 50% ethanol in water as the extraction solvent and shaking in a 60 °C water bath for 3 h. A total of 8 phenolic acids and 14 flavonoids were separated and identified within 55 min by using a Poroshell 120 EC‐C18 column with detection at 280 nm, flow rate at 0.8 mL/min, column temperature at 35 °C, and a gradient solvent system of 0.1% formic acid in water and acetonitrile. Two internal standards caffeic acid and kaempferol‐3‐O‐rutinoside were used for quantitation of phenolic acids and flavonoids in djulis respectively. The amounts of phenolic acids ranged from 11.5 ± 0.8 &mgr;g/g (caffeoyl‐putrescine‐derivative (2)) to 1855.3 ± 16.9 &mgr;g/g (hydroxylphenylacetic acid pentoside), while the flavonoids ranged from 19.93 ± 2.29 &mgr;g/g (quercetin‐3‐O‐(coumaryl)‐rutinoside‐pentoside (1)) to 257.3 ± 2.05 &mgr;g/g (rutin‐O‐pentoside (2)). A high recovery (89.68–97.20%) and high reproducibility was obtained for both phenolic acids and flavonoids with the relative standard deviation (RSD) for the latter ranging from 0.09–8.22% (intra‐day variability) and 0.80–8.48% (inter‐day variability). This method may be applied to determination of both phenolic acids and flavonoids in food products and Chinese herbs.