Agarose hydrogel containing immobilized pH buffer microemulsion without increasing permselectivity

TALANTA

卷:177

Article

Crespi, Miguel Coll¹  Crespo, Gaston A.²  Xie, Xiaojiang³  Touilloux, Romain¹  Tercier-Waeber, Marylou¹  Bakker, Eric¹ 

[1] Univ Geneva, Dept Inorgan & Analyt Chem, Quai Ernest Ansermet 30, CH-1211 Geneva, Switzerland

[2] KTH Royal Inst Technol, Appl Phys Chem Div, Tekn Ringen 30, SE-10044 Stockholm, Sweden

[3] Southern Univ Sci & Technol, Dept Chem, Shenzhen 518000, Peoples R China

关键词: Heterogeneous pH buffer;    Tridodecylamine;    Ionophore;    Agarose;    Hydrogel membranes;    Permselectivity;    Donnan failure;   

DOI  :  10.1016/j.talanta.2017.08.053

来源: Elsevier

【 摘 要 】

A heterogeneous pH buffer based on a colloidal emulsion containing ion-exchanger and lipophilic base is described that can be integrated into hydrogels without affecting their ion-exchange properties. Each sphere works on the basis of reversible ion-exchange of hydrogen ions with solution cations, acting as a pH buffer while staying removed from solution in the nonpolar core of the spheres. The ion-exchange mechanism is supported by titration experiments in aqueous emulsion, showing that the nature and concentration of the exchanging solution cations influences the buffer action, with increasing lipophilicity moving the equilibrium to lower pH values. Agarose gels with entrapped pH buffer emulsions and mounted in a transport cell are shown by zero current potentiometry to exhibit negligible permselective properties above an ionic strength of 1 mM, a behavior no different from unmodified agarose, with an observed ion-exchanger concentration of 7 mM in dry agarose. This suggests that such pH buffers do not give rise to substantial ion-exchange properties of the gel material. In a first attempt to control the pH in the vicinity of an electrode surface by this approach, the emulsion was entrapped in an agarose gel in direct contact with a pH electrode, demonstrating the ability to buffer such gel films.

【 授权许可】

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