Quantitation of the Hydroxycinnamic Acid Derivatives and the Glycosides of Flavonols and Flavones by UV Absorbance after Identification by LC-MS

• Published in: Journal of agricultural and food chemistry 2012-01, Vol.60 (2), p.544-553
• Main Authors: Lin, Long-Ze, Harnly, James, Zhang, Ren-Wei, Fan, Xian-E, Chen, Hui-Jia
• Format: Article
• Language: English
• Subjects: absorbance; Biological and medical sciences; Calibration; Chromatography, High Pressure Liquid - methods; Chromatography, High Pressure Liquid - standards; Coumaric Acids - analysis; Coumaric Acids - chemistry; Flavones - analysis; Flavones - chemistry; flavonols; Flavonols - analysis; Flavonols - chemistry; Food Analysis - methods; Food industries; Fundamental and applied biological sciences. Psychology; glycosides; Glycosides - analysis; Glycosides - chemistry; Lactuca - chemistry; Mass Spectrometry - methods; Onions - chemistry; Reference Standards; Spectrophotometry, Ultraviolet - methods; Tea - chemistry; vacuum drying; white tea
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf204612t

A general approach was developed to quantify hydroxycinnamic acid derivatives and the glycosides of flavonols and flavones using UV molar relative response factors (MRRFs). More than 90 standards were analyzed by LC-MS and divided into five groups based on the λmax of their band I absorbance profiles. For each group, a commercially available standard was chosen as the group reference standard. Response factors were determined for each standard in each group as purchased (MRRF) and, when possible, after vacuum drying (MRRFD). The MRRFD values for 17 compounds whose λmax values fell within ±2 nm of the group reference standard were 1.01 ± 0.03. MRRF values for compounds whose λmax values fell within ±10 nm of the group reference standard were 0.96 ± 0.13. Group reference standards were used to quantify 44 compounds in Chinese lettuce, red onion, and white tea. This approach allows quantitation of numerous compounds for which there are no standards.