Simultaneous determination of lobetyolin and atractylenolide III in Codonopsis Radix by dispersive liquid-liquid microextraction based on hydrophobic deep eutectic solvent

Abstract

In order to achieve the determination and quantification of trace lobetyolin and atractylenolide III in Codonopsis Radix, a procedure of dispersive liquid-liquid microextraction utilizing a hydrophobic deep eutectic solvent as the extractant combined with high performance liquid chromatography was developed. The primary variables affecting the extraction process, including the type, ratio and volume of extractant, pH and salt concentration in sample phase, type and volume of dispersant, extraction time, centrifugal speed and time were optimized. In this experiment, the deep eutectic solvent prepared by methyltrioctylammonium chloride and n-butanol was the best extractant. The both target analytes showed good linearity (r2 > 0.990) in their respective linear ranges (0.01–2.5 µg/mL and 0.009–2.0 µg/mL). And the limits of detection and quantification were 6 × 10−4 and 2 × 10−3 µg/mL for lobetyolin, 3 × 10−3 and 9 × 10−3 µg/mL for atractylenolide III. The enrichment factors were 37 for lobetyolin and 154 for atractylenolide III respectively. The relative standard deviations of precision were 1.2–6.4% and the spiked recovery values were in the range of 87.6–114.7% with the relative standard deviations of 1.5–4.7%. It is successful to objectively and clearly distinguish the three origins of Codonopsis Radix by comparing the contents of the both analytes with proposed method.