School of Pharmacy, Shanxi Medical University, Taiyuan, Shanxi, 030001, P.R. China.
School of Pharmacy, Shanxi Medical University, Taiyuan, Shanxi, 030001, P.R. China.
J Chromatogr A. 2022 Mar 15;1666:462858. doi: 10.1016/j.chroma.2022.462858. Epub 2022 Jan 29.
A switchable deep eutectic solvent-based liquid-phase microextraction was proposed and applied to the preconcentration and determination of liposoluble quality-markers of diterpenoid quinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in traditional Chinese medicine coupled with high performance liquid chromatography-ultraviolet detection. In the procedure, the hydrophilic deep eutectic solvent of diethanolamine-hexanoic acid (molar ratio 1:1) was prepared and added into the sample phase as an extractant, and a homogeneous solution was formed under slight vortex stirring. After the addition of HCl solution, the deep eutectic solvent miscible with the sample phase was converted to hydrophobic form, and a cloudy solution was generated. Then, the upper hydrophobic layer enriching the target analytes was collected through centrifugation for high performance liquid chromatography analysis. Several critical parameters affecting the extraction performance including the composition and consumption of switchable deep eutectic solvent, the type and amount of acid, salt amount and extraction time were investigated and optimized. Moreover, the structures of the deep eutectic solvent and the recovered hydrophobic layer were both characterized using Fourier transform infrared spectroscopy, further demonstrating the switching mechanism of the extractant during the extraction process. Under the optimal conditions, enrichment factors of diterpenoid quinones ranged from 59 to 274. Good linearities (r≥0.9963), low detection limits (0.5-0.7 ng/mL), satisfactory precisions (relative standard deviations 0.5%-8.6%) and accuracies (recoveries 94.6%-104.6%) were also obtained. Comparing the proposed switchable deep eutectic solvent-based liquid-phase microextraction with other published methods, the characteristics of the procedure were summarized. The developed method was successfully applied for the preconcentration of four liposoluble diterpenoid quinones from a traditional Chinese herbal medicine of Salvia Miltiorrhiza.
一种可切换的深共晶溶剂液相微萃取被提出并应用于脂溶性质量标志物（二氢丹参酮 I、隐丹参酮、丹参酮 I 和丹参酮 IIA）的预浓缩和测定，该方法与高效液相色谱-紫外检测相结合。在该过程中，制备了亲水的二乙醇胺-己酸深共晶溶剂（摩尔比 1:1），并作为萃取剂加入到样品相中，在轻微涡旋搅拌下形成均相溶液。加入 HCl 溶液后，与样品相混溶的深共晶溶剂转化为疏水性形式，生成混浊溶液。然后，通过离心将富含目标分析物的上层疏水性层收集起来进行高效液相色谱分析。考察并优化了影响萃取性能的几个关键参数，包括可切换深共晶溶剂的组成和用量、酸的类型和用量、盐的用量和萃取时间。此外，还使用傅里叶变换红外光谱对深共晶溶剂和回收的疏水性层的结构进行了表征，进一步证明了萃取过程中萃取剂的切换机制。在最佳条件下，二萜醌的富集因子范围为 59-274。获得了良好的线性（r≥0.9963）、低检测限（0.5-0.7 ng/mL）、令人满意的精密度（相对标准偏差为 0.5%-8.6%）和准确度（回收率为 94.6%-104.6%）。将所提出的可切换深共晶溶剂液相微萃取与其他已发表的方法进行比较，总结了该方法的特点。该方法成功应用于从丹参传统中草药中预浓缩四种脂溶性二萜醌。
