Dual ionic liquid-immobilized silicas for multi-phase extraction of aristolochic acid from plants and herbal medicines

A convenient, and efficient multi-phase extraction method was used to isolate aristolochic acid from real samples. To increase the efficiency, a new dual ionic liquid-immobilized silica was used as a sorbent and the effects of the adsorption conditions were investigated. IM-BIM@Sil in a methanol/water (60:40, v/v) solution at 60 °C extracted the highest amount of aristolochic acid (16.69 mg/g) compared to the other sorbents examined. The sorbent was then applied to the multi-phase extraction of aristolochic acid. After extraction eight times, 2.4–70.9 × 10 −3 mg/g of aristolochic acid was isolated from nine real samples after several washing and elution steps. The recoveries of aristolochic acid ranged from 70.0% to 110.6% with relative standard deviations of 3.5%–9.1%, highlighting the accuracy of this method.