[Determination of quercetin in human serum by liquid chromatography-mass spectrometry]

To establish LC-MS method to determine quercetin in human serum.

Serum samples were extracted by acetone- methanol and hydrolyzed by β- glucuronidase. The Agilent Poroshell 120 EC C_(18)( 50 mm × 4. 6 mm, 2. 7 μm) was used and acetonitrile( B) and 1% formic acid( A) as the mobile phase with gradient elution. Flow rate was 1. 0 m L / min and column temperature 40℃. Liquid chromatography-tandem mass spectrometry( LC-MS) with electrospray ionization( ESI~-)was performed in a negative mode and using selective negative ion detection. Detected ion m / z was 301. 1( quercetin) and 285. 1( fisetin).

The method had good linearity in the concentration ranges of 1- 200 ng / m L. The correlation coefficient( r) was0. 9998. The detection limits of quercetin was 0. 025 ng / m L. Interday precision( RSD)was 4. 98%-8. 35%. Intraday precision( RSD) was 7. 62%-9. 73%. The recoveries of quercetin in serum was 97. 4%-112. 8%.

The established method is sensitive and reproducible, and can be used in determination of quercetin in human serum.