Automated In-Injector Port Conversion of Aristolochic Acids to Aristolic Acids for Enhanced HPLC Fluorescence Detection

Abstract

Aristolochic acids (AAs) and the herbs containing them are recognized human carcinogens. Emerging evidence indicates that AAs are also food and environmental contaminants, posing significant risks to human health. This study developed a highly sensitive AA detection method by combining automated in-injector denitration with HPLC coupled with fluorescence detection (HPLC–FLD). The method converts non-fluorescing AAs into fluorescing aristolic acids (ARs) through a dithionite-mediated reaction directly within the HPLC injector port. Following validation for accuracy and precision, this method was applied to measure AAs in herbal medicine and soil samples collected from an herbal cultivation field. This approach, featuring automated in-injector derivatization, offers improved sensitivity and resolution, and selectivity while being less labor-intensive than existing methods for AAs analysis, obviating the need for sample enrichment or cleanup. The adaptable derivatization strategy also shows promise for the sensitive detection of other chemical species with appropriate derivatization agents.