The first attempt at continuous-mode separation of racemic and meso-2,3-butanediol with high purities using a simulated-moving-bed process

Continuous chromatography system with 6-zone and 18-column dynamic tandem connection technique for the enrichment of total flavonoids from Epimedium koreanum Nakai

Natural flavonoids have been shown to have many pharmacological activities. Efficient and continuous enrichment of total flavonoids with high content and low mobile phase usage from complex natural products is greatly needed at the moment. In this study, a new continuous chromatography system (CCS) with 6 zones and the 18-column dynamic tandem connection technique was developed and used to enrich total flavonoids from Epimedium koreanum Nakai (EKN). The 18 columns were divided into 6 zones, and the principle of a dynamic series of three columns was adopted for each zone to achieve continuous automatic separation and enrichment of total flavonoids under the control of a logic control valve. The CCS separation conditions were established based on single-column chromatography and a theoretical calculation model of the CCS. By means of the self-designed device and method, 485.11±3.16 g of total flavonoids were isolated from 16.2 kg of EKN. It is worth noting that the total content of 18 types of flavonoids in the samples enriched by the CCS was increased from 2.84±0.07% to 88.29±0.22%, the total recovery rate was 92.20±0.38%, and the RSD of each flavonoid was less than 5.0%. Furthermore, compared with single-column chromatography filled with the same volume of chromatography filler, the entire process saved about 2/3 of the mobile phase usage. In summary, the developed device and method could efficiently and continuously enrich total flavonoids from EKN with high-content and low mobile phase usage and would have a wide application prospect in the separation and enrichment of natural products.