Simultaneous extraction and enrichment of alkaloids from lotus leaf by in-situ cloud point-reinforced ionic liquid assisted mechanochemical extraction technology

Abstract

A novel, green and efficient in-situ cloud point-reinforced ionic liquid-assisted mechanochemical extraction (IS-CPR-IL-MCE) technique coupled with ultrahigh performance liquid chromatography was established to simultaneously extract, concentrate and separate five alkaloids (including liensinine, isoliensinine, neferine, O-demethyl nuciferine and nuciferine) from lotus leaf. The parameters affecting the extraction efficiency of target analytes, such as the amount of IL, surfactant and salt, grinding time, pH, enrichment temperature and time were systematically studied and optimized by single-factor and multifactor experiments. The highest extraction yield of alkaloids was obtained by IS-CPR-IL-MCE under the following conditions: 0.23 g of 1-dodecyl-3-methylimidazolium bromide, 0.37 g of Triton X-100, 7.73 of pH, 5 min of milling time, 2.5 g of (NH4)2SO4, 60 ℃ and 20 min of enrichment temperature and time. The developed method exhibited a good linearity in the range of 0.5–100.0 μg/mL with the coefficients of correction more than 0.9992, low limit of detection of 8.0–11.2 ng/mL, acceptable reproducibility below 4.45%, and satisfactory recovery in the range of 80.4–93.7% The results demonstrated that the proposed method was successfully applied to the extraction of alkaloids from lotus leaf.