Application Research For Separation And Determination Of Chlorogenic Acid Isomers In Honeysuckle And Its Preparations By HPCE Based On Self-synthesized Ionic Liquids

Objective:In the first part of the article,aiming to establish a simple,comprehensive and efficient capillary electrophoresis method for simultaneous separation and determination of chlorogenic acid isomers in honeysuckle using[N-methylimidazole-β-cyclodextrin][bromide]as separation selector.In the last chapter,pressure-assisted capillary electrophoresis was used to determine rapidly and efficiently the pK_avalues of chlorogenic acid isomers.Methods:1.The experiments was carried out using a P/ACE MDQ system equipped with a diode array detector.And an uncoated fused-silica capillary(40.2 cm×75μm id)with an effective length of 30 cm was used.Under the injection pressure of 0.5 psi and the injection time of 5 s,the effects of the type and concentration of buffer solution,the type and concentration of self-synthesized ionic liquid,the p H of background electrolyte,operating voltage and temperature on the separation of the five chlorogenic acid isomers were investigated.Finally,the optimum separation conditions were as follows:50 mmol/L ammonium acetate(p H=4.8)as buffer solution,and the mass fraction of 0.7%N-methylimidazole bromide-β-cyclodextrin ionic liquid([NMIM-β-CD][Br])as additive,detection wavelength 237 nm,operating voltage 15 k V,operating temperature 25℃.The method was validated and applied to the separation and analysis of Honeysuckle and its preparations.2.The experiments were performed by using a P/ACE MDQ system equipped with a diode array detector.The separation was carried out in an uncoated fused-silica capillary(40.2 cm×75μm id,30 cm to detector).By examining the influence of injection pressure,type and concentration of buffer,and washing procedure,the Origin software was used for nonlinear regression analysis to determine the pK_avalues of five chlorogenic acid isomers.Results:Under the optimal separation conditions,five chlorogenic acid isomers achieved completely separation within 10 minutes.A good linearity was obtained with correlation coefficients from 0.9994 to 0.9998;The limits of detection(LOD)and limits of quantitation(LOQ)ranged from 0.6 to 2.8μg/m L and from 2.2 to 9.5μg/m L,respectively.The precision is good.The intra-day precision of the five chlorogenic acid isomers range from 1.0%to 1.9%,and the intra-day precision range from 1.2%to 2.6%;The average recoveries of each analyte in the actual sample range from 98.0%to 101.8%.The established method in this paper was successfully applied to simultaneous determine five chlorogenic acid isomers in Honeysuckle and its medicinal preparations.The measured pK_avalues for the five chlorogenic acid isomers were Chlorogenic acid(3.86),Cryptochlorogenic acid(4.01),Neochlorogenic acid(3.85),Isochlorogenic acid A(3.48)and isochlorogenic acid B(3.63),respectively.Conclusion:A simple,comprehensive,and efficient capillary electrophoresis method using a self-synthesized ionic liquid[NMIM-β-CD][Br]as a separation selector was developed for the simultaneous separation and determination of five chlorogenic acid isomers in Honeysuckle,morover,successfully used in the separation and content determination of the above analytes in Honeysuckle and its medicinal preparations.This method can provide a scientific guidance for the quality control of Honeysuckle and its preparations.In addition,the pK_avalues of were successfully determined five chlorogenic acid isomers by pressure-assisted capillary electrophoresis.