Simultaneous analysis of six aristolochic acids and five aristolactams in herbal plants and their preparations by high-performance liquid chromatography–diode array detection–fluorescence detection

Aristolochic acid analogues, including aristolochic acids (AAs) and aristolactams (ALs), are known to be nephrotoxic, carcinogenic and mutagenic. In this paper, a high-performance liquid chromatography–diode array detection–fluorescence detection (HPLC–DAD–FLD) method was developed for the simultaneous determination of six AAs together with five ALs. Baseline separation was obtained on an ODS C18 analytical column with 0.2% HAc/methanol gradient elution. The hyphenation of DAD and FLD allows the method to directly meet the analysis requirements of most herbal plants with high sensitivity and selectivity. For trace analysis, aristolochic acids were reduced to their corresponding aritstolactams in acidic solution containing iron powder, and then high sensitive detection and quantification were carried out. The method was successfully validated in the matrices of various Aristolochiaceae plants and their preparations. Linearities of around 3–4 orders of magnitude were obtained with correlation coefficients exceeding 0.9970. The detection limits were decreased to 0.2 ng/ml. Satisfactory intra-day and inter-day precisions were achieved with RSDs less than 5.74%, and the average recovery factors were in the range of 94.5–99.2%.