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With frontal analysis(FA),the dependence of adsorption isotherms of insulin on the composition of mobile phase in reversed phase liquid chromatography (RPLC) has been investigated,This is also a good example to employ the stoichiometric displacement theory (SDT) for ivestigating solute adsorption in physical chemistry.Six kinds of mobile phase in RPLC were employed to study the effects on the elution curves and adsorption isotherms of insulin.the key points of this paper are:(1) the stability of insulin due to delay time after preparing,the organic solvent concentration,the kind and the concentration of ion-pairing agent in mobile phase were found to affect both elution curve and adsorption isotherm very seriously.(2)To obtain a valid and comparable result,the composition of the mobile phase employed in FA must be as same as possible to that in usual RPLC of either analytical scale or preparative purpose.(3)Langmuir Equation and the SDT were employed to imitate these obtained adsorption isotherms.The expression for solute adsorption from solution of the SDT was found to have a better elucidation to the insulin adsorption from mobile phase in RPLC.  相似文献   
2.
IntroductionFrontalchromatography (FC) ,anoldbranchinliquidchromatography (LC) ,1hasbeensuccessfullyem ployedinthesolutionofmanytheoreticalaswellasap pliedproblems—suchasmeasuringbindingconstantbe tweencomponents2 andkineticparametersofchemicalreactions ,3 ads…  相似文献   
3.
With four kinds of mobile phases,methanol-water,ethanol-water,2-propanol and acetonitrile-water(all containing 0.1%rifluroacetic acid),the displacement between solute and solvent in RPLC was proved to be universal in frontal analysls(FA).Based on the measured Z value in usual RPLC to be a constant and the quantitative determination of methanol increment in mobile phase in FA,the stoichiometric displacement(SD)between insulin and methanol was directly proved by the experiment.The SD was also proved to occur only on about the one-fourth of the maximum amount of adsorbed methanol in the bonded phase layer(BPL)without any dynamic problem of mass transfer,while in FA,the SD firstly occurs on the surface of the BPL and then gradually sinks into the deeper sites companied with a dynamic problem.Although the displaces soplvent by the same solute is less in the former case,the SD is independent of how deep of the solute enters the BPL.In addition,the adsorbed amount of solute on and adsorbent not only depends on the numbers of the adsorbed layer on the adsorbent surface,but also on the extent of the complete removal of the displace able solvent in the BPL.The pyhsical fundamental of the SD and the methodoloby for investigation were also discussed.  相似文献   
4.
With insulin methanol-water,and the ion-pairing agent,hydrochloric acid and trifluroacetic acid(TEA),the character of the first plateau(FP)on the elution curve of frontal analysis in reversed phase liquid chromatography(RPLC)was investigated by on-line UV-spectrometry and identified with nuclear magnetic resonance(NMR) spectrometry and mass spectrometry.The profile of the FP is the same as that of a usual elution curve of methanol in frontal analysis(FA).When the insulin concentration was limited to a certain range,the height of the FP was found to be proportional to the insulin concentration in mobile phase and its length companying to shorten,The FP profile on the intersection of two tangents reflects the components of the microstructure in the depth direction of the bonded stationary phase layer and the desorption dynamics of the displaced components.The displaced methanol was quantitatively determined by NMR and on-line UV spectrometries.TFA with high UV absorbance can not be used as an ionpairing agent for the investigation of the FP in RPLC,but if can be used as a good marker to investigate the complicated transfer process of components in the stationary phase in RPLC.A stoichiometric displacement process between solute and solvent was proved to be valid in both usual and FA in RPLC.From the point of view of dynamics of mass transfer, the solutes can only contact to the surface of stationary phase in usual RPLC,while solute can penetrate into it in FA of RPLC.The solvation of insulin in methanol and water solution as an example indicating the usage of the FP in the FA was also investigated in this paper.  相似文献   
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