Quantification of aristolochic acids I and II in herbal dietary supplements by ultra-high-performance liquid chromatography–multistage fragmentation mass spectrometry

Abstract

A rapid, selective and sensitive ultra-high-performance liquid chromatography–multistage fragmentation mass spectrometry (UHPLC-MS³) method was developed and evaluated for the determination of aristolochic acids I and II (AA I and II) in herbal dietary supplements. A hybrid triple quadrupole/linear ion-trap mass spectrometry was used to monitor MS³ ion transitions m/z 359.2 > 298.1 > 268.0 and m/z 329.2 > 268.2 > 238.0 to detect AA I and II, respectively. The extraction and clean-up of target analytes from dry powdered samples was performed using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure. Herbal liquid extracts were analysed directly. Average recoveries ranged from 89% to 112%, with relative standard deviations (RSDs) ranging from 3% to 16%. Limits of quantification (LOQs) estimated for three selected matrices were as follows (AA I/II): 5/10 ng g⁻¹ (tablets); 25/50 ng g⁻¹ (capsules); and 2.5/5.0 ng ml^−l (liquid herbal extract). The method was applied in a limited survey of 30 herbal products marketed in the United States via the Internet. AA I and II were detected in 20% and 7%, respectively, of tested samples.

Graphical Abstract

Keywords:

• herbal dietary supplements
• aristolochic acid
• LC-MS

Acknowledgements

L. V. acknowledges the support of an appointment to the Research Participation Program at the Center for Food Safety and Applied Nutrition administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the US Food and Drug Administration.