Determination of 19 rhubarb constituents by high-performance liquid chromatography-ultraviolet-mass spectrometry.
Rhubarb (Rhei rhizoma), a commonly used Chinese herb, contains anthraquinones, anthrones, galloylglucoses, stilbenes, and flavan-3-ols compounds, etc. as major constituents. Using 19 of these compounds as markers, an HPLC-UV-MS method was developed to estimate the quality of rhubarb samples within a period of 70 min. Extracts were analyzed with a Cosmosil 5C18-MS column and eluted with a gradient comprising an aqueous solution of acetic acid and methanol at a flow rate of 0.9 mL/min. Peaks were detected by absorbance measurements at 254 nm (6 and 8-19) and 280 nm (1-5 and 7), and the peaks of the marker substances were identified from their UV spectra and MS fragmentation patterns. The proposed method yielded a peak-area ratio RSD value with an intraday SD falling within 0.71-1.78% and an interday SD within 0.78-1.98% at a detection limit of 0.2-3.2 microg/mL. The ESI negative ion mode was used to collect data (molecular weight, CID fragments from MS and MS/MS spectra) for 19 compounds from four types of structure categories: anthraquinones, dianthrone glycosides, stilbenes, and galloylglucosides. The information gathered can be used to identify the structures of various peaks appearing in the LC chromatograms of rhubarb samples.
Lin
Ching-Che
CC
Chemistry Department, National Taiwan Normal University, 88, sec 4, Tingchow Rd., Taipei, Taiwan. chingchekimo@yahoo.com.tw
Wu
Chuan-I
CI
Lin
Ta-Chen
TC
Sheu
Shuenn-Jyi
SJ
D000880:Anthraquinones / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D012250:Rheum / Q000737:chemistry*; D012676:Senna Extract; D000081226:Sennosides; D013056:Spectrophotometry, Ultraviolet; D013267:Stilbenes / Q000737:chemistry
D000880:Anthraquinones; D000081226:Sennosides; D013267:Stilbenes; D012676:Senna Extract