Selectively modified microfluidic chip for solvent extraction of Radix Salvia Miltiorrhiza using three-phase laminar flow to provide double liquid-liquid interface area

Radix Salvia Miltiorrhiza, a famous herb medicine is widely used in China and limitedly used in USA, Japan, and other countries for the treatment of cardiovascular and cerebrovascular diseases. This herb medicine has two groups (non-polar and polar) of active ingredients with distinct clinical effects, and thus theses ingredients should be separately used to enhance therapeutic efficacy and reduce side effect. In this article, as an alternative of conventional mechanical shaking and separatory funnel, laminar flow extraction in microfluidic chip is proposed to separate the two kinds of herb ingredients. Compared with conventional methods, microfluidic chip provides continuous extraction, less labor intensity, and better performance. Furthermore, we employ three-phase laminar flow to provide double liquid-liquid interface area, circumventing the low efficiency of two-phase laminar flow. Therefore, the extraction ratio is dramatically improved to 92% (tanshinone IIA). To predict the extraction ratio, a straightforward theoretical model is also established and agrees well with the experimental results. This microfluidic chip would be a powerful technical platform for handling complicated natural products.