Determination of aristolochic acids in medicinal plant and herbal product by liquid chromatography-electrospray-ion trap mass spectrometry

This paper describes a liquid chromatography-electrospray-ion trap mass spectrometry (LC-ES-ITMS) method for the determination of aristolochic acid I and II (AA-I and AA-II) in medicinal plants and Chinese herbal remedies. A reversed phase C-18 column with gradient elution was utilized. The effects of mobile phase additives, acetic acid and ammonium acetate, on LC separation and ES ionization were investigated. For both AA-I and AA-II, the [M + NH4](+) ion was found to be the precursor ion for target MS/MS analysis. The MS/MS product ion, [M+H-44](+), was used for the quantitative measurement of AA-I and AA-II. The linearity was good from 0.03 to 5 mug ml(-1) and good correlation (r(2) = 0.999) over the range examined was determined for both AA. The detection limit based on a signal-to-noise ratio of three was 0.012 and 0.015 mug ml(-1) for AA-I and AA-II, respectively. Various Chinese herbal remedies obtained from renal failure patients and medicinal plants were examined by this newly developed method. (C) 2003 Elsevier Science B.V. All rights reserved.