Simultaneous Determination of the Flavonoids and Limonoids in Citrus junos Seed Shells Using a UPLC–DAD-ESI/MS

ABSTRACT

Citrus junos seeds (CS) have been traditionally used for the treatment of cancer and neuralgia. They are also used to manufacture edible oil and cosmetic perfume. A large amount of CS shells without oil (CSS) are discarded after the oil in CS is used as foods or herbal remedy. To efficiently utilize CSS as a by-products, it needs to be studied through chemical analysis. Therefore, we developed an ultra-performance liquid chromatography (UPLC)–diode array detection (DAD) method for simultaneous determination and quantitative analysis of five components (two flavonoids and threes limonoids) in CSS. A Waters Acquity UPLC HSS T3 column C18 (2.1 × 100 mm, 1.8 μm) was used for this separation. It was maintained at 40 oC. The mobile phase used for the analysis was distilled water and acetonitrile with gradient elution. To identify the quantity of the five components, a mass spectrometer (MS) with an electrospray ionization (ESI) source was used. The regression equation showed great linearity, with correlation coefficient ≥ 0.9912. Limits of detection (LOD) and limits of quantification (LOQ) of the five compounds were 0.09 – 0.13 and 0.26 – 0.38 μg/mL, respectively. Recoveries of extraction ranged from 97.45% to 101.91%. Relative standard deviation (RSD) values of intra- and inter-day precision were 0.06 – 1.15% and 0.19 – 0.25%, respectively. This UPLC–DAD method can be validated to simultaneously analyze quantities of marker flavonoids and limonoids in CSS.