An electrochemical approach to study water–d(−)fructose interactions

Abstract

Water–d(−)fructose interactions have been studied for the first time by applying electrochemical technique using a redox-active probe ferrocenecarboxylic acid (FCA). Cyclic voltammetry was employed to study electrochemical behavior of FCA in aqueous solution of cetyltrimethylammonium bromide (CTAB) both in absence and presence of d(−)fructose. A three electrode system with a glassy carbon electrode as working electrode was used for this purpose. The concentrations of CTAB, d(−)fructose and FCA were varied in order to correlate electrochemical responses with the dissolved states to interpret water–d(−)fructose interactions. The anodic and the cathodic peak current, as well as, the apparent diffusion coefficient of FCA in micellar solution of CTAB increase with added d(−)fructose at low concentrations; while a reverse trend is observed at high d(−)fructose concentrations. The additions of d(−)fructose at low concentrations raise the critical micelle concentration (CMC) of CTAB, while high concentrations of d(−)fructose favor micellization. Analyses of experimental results indicate that d(−)fructose at lower concentrations behaves as a structure breaker of the water cluster, while that at higher concentrations acts as a structure maker. We have been able to successfully demonstrate that FCA can serve as a standard electro-active probe for studying the interaction of a non-electro-active guest with water.