Design Of An Automatic Vacuum Liquid Chromatography Device And Its Application In The Separation And Purification Of Chinese Herb Components

Preparative chromatography which serves as a general tool of isolation and purification of Chinese herb components,has a variety of problems such as human consumption,poor systematicness and repeatability and so on,so it now needs automatic and efficient chromatographic equipment urgently.Vacuum liquid chromatography is a convenient and high efficient chromatographic device,and applying automation to it can dramatically improve the advantages in separation,which is significant to the automatic and effective separation of traditional Chinese medicine.This paper developed an automatic vacuum liquid chromatography(AUTO-VLC)device,which used programmable logic controller(PLC)to realize the automatic control and monitoring of the separation process.By using the petroleum ether extracts of Schisandra chinensis(Turcz)Baill.as a research object,AUTO-VLC were applied to the component separation and purification,and meanwhile an new method used for the VLC separation parameter screen by using multiple developments TLC was developed and confirmed.The device is comprised of electrical automation control system,solvents system,10 in-1 out switching valve,1 in-3 out switching valve,dynamic axis compress chromatography column with three diameters,3 in-1 out fraction valve,1 in-10 out fraction valve and fraction collection system.The dynamic axial compression chromatographic columns were adopted to realize the stability requirement of the column bed,and to ensure the high efficiency of chromatographic columns.Among in,the core technology of this equipment is the PLC S7-200.The input part of the S7-200 collected signal from the switching valve,the output part of driving unit controlled the switch of electromagnetic valves,air cylinder and the movement direction of the cylinder,which realized the automatic control and monitoring of the mobile phase changing,column selecting,separation time setting and fraction collectings.And this realized fast,effective and intelligent control of natural drug separation and purification process through VLC.The separation result of chemical component from Schisandra chinensis petroleum ether phase by using this device shows: 6 fractions(S1-S6)were obtained with different components separated by 150 mm diameter AUTO-VLC from 100 g Schisandra chinensis petroleum ether phase.A new method used for the VLC separation parameter screen by using multiple developments TLC was developed and confirmed.The methods was: the initial mobile phase of AUTO-VLC was selected by taking all the target compounds Rf ranging from 0 to 0.45 for fist development on TLC;gradient elution ratio was selected according to k value(the slope of the linear function of Rf value and development times on TLC)and resolution of target compounds;elution times were calculated by the formula n≈ΔRf/k.13 components and 4 compounds with the purity more than 85% were separated from S5 in selected condition.It took only17h.The development of AUTO-VLC device is rapid,effective and automatic for the separation of complex components in traditional Chinese medicine.And the method used for the VLC separation parameter screen is feasible.AUTO-VLC device has the characteristics of fast and convenient operation and ideal effects,which are significant to the automatic and systematic separation of traditional Chinese medicine.