Studies On The Ion Transfer Reactions At The Liquid/liquid Interface Modified By Functionalized Hybrid Membrane

In this paper,on one hand,the ion transfer reaction of leucovorin ion across the water/1,6-dichlorohexane（DCH）interface modified by hybrid mesoporous silica membrane（HMSM）was studied by employing cyclic voltammetry（CV）,differential pulse voltammetry（DPV）and chronocoulometry.It was found that the electrochemical behaviors of ion-transfer of leucovorin ion across such a membrane-modified W/DCH interface are closely related with the ionic surfactant cetyltrimethylammonium bromide（CTAB）,self-assembled within the silica nanochannels of the HMSM.According to the linear relationship between the peak current of CV corresponding to the ion transfer of leucovorin ion from water to DCH and the square root of scan rate,as well as the equation of Randles-Sev?ik,the diffusion coefficient of leucovorin ion in water is calculated to be about 2.036×10^-8 cm²/s.In addition,the standard reaction rate constant of the ion transfer of leucovorin ion at such a membrane-modified W/DCH interface was estimated to be about 2.72×10^-3 cm/s via chronocoulometry.This work is expected to help understanding the transport processes of leucovorin across biomembrane in bioscience and provide an elctrochemical method to detect calcium leucovorin.On the other hand,a novel hybrid periodic mesoporous organosilica（PMO）functionalized membrane,hybrid PMOmembrane composed of SiO2@B-aptes inside the channels of PET was successfully synthesized via the aspiration-induced infiltration method,and it was characterized by scanning electron microscopy（SEM）,N₂ adsorption–desorption and thermal gravimetric analysis（TG）.In addition,such a functionalized membrane was applied to liquid/liquid Interface（L/L interface）electrochemistry,and the transfer behaviors of some ions,including drug molecule enalapril（ENA）,were studied at the the functionalized L/L interface modified by the hybrid PMO membrane for the first time by employing cyclic voltammetry（CV）and differential pulse voltammetry（DPV）.Interestingly,it was found that the detection sensitivity of ENA was increased from 0.985 nA?mM^-1（hybrid PMO membrane）to 6.86 nA?mM^-1（bare PET membrane）,and the value of limit of detection（LOD）reduced from 2.1μM（bare PET membrane）to 0.29μM（hybrid PMO membrane）,which indicates that the functionalization of L/L interface by using hybrid PMO membrane is helpful to improve the detection of ENA.Moreover,when the pH of aqueous solution is kept at low enough（pH¹）,an extra CV peak appeared at 0.5 V corresponding to the anion transfer of ENA^-,which could not be found at the same condition by using bare PET membrane.According to the mesostructure of hybrid PMO membrane,such an interesting phenomenon could be ascribed to H-bond effect and electrostatic interaction occurring between the PMO and the ENA^-.According to the Randles-Sev?ik equation,the diffusion coefficient of HHENA+in the aqueous phase was calculated to be about 1.055×10^-77 cm²?s^-1（pH⁶）,while the diffusion coefficient of HHENA+was about 1.071×10^-7 cm²?s^-1and the diffusion coefficient of ENA^-was about 4.768×10^-7 cm²?s^-1（pH¹）.Additionally,the partition diagrams of ENA at the W/DCH werestudied,which is helpful to understand the lipophilicity of drug moleculeIn conclusion,two kinds of hybrid mesoporous membranes were applied to modify the liquid/liquid interface and to study the ion transfer reactions occurring at such membrane-modified liquid/liquid interface.The results show that the functionalization of liquid/liquid interface by using hybrid meosporous membrane including hybrid PMO membrane can improve the detection of durg ion.Moreover,such a functionalized liquid/liquid interface can mimic the ion-channel in the biomembrane,which helps to understand the ion-transfer behavior across biomembrane.