Adsorption of Ibuprofen and Dopamine on Functionalized Gold Using Surface Plasmon Resonance Spectroscopy at Solid-Liquid Interface

Ultrathin gold nanofilms (≈ 50 nm) are suitable for detection of adsorbed molecules at solidliquid interface of various sizes due to their surface plasmon resonance (SPR) properties. This SPR technique makes it possible to study the surface adsorption in nanomol range amount on gold surfaces of a maximum of one mm and to determine the adsorbed amount as a function of equilibrium concentration. Adsorption of L-cysteine, L-glutathione, ibuprofen and dopamine on the gold surface was examined. Moreover, the binding capability of ibuprofen and dopamine molecules on the gold surface functionalized by L-cysteine and L-glutathione was studied as well. Adsorption isotherms were recorded using the flow measuring technique, which allows determination of the amount of adsorbed material even in the nmol/cm order of magnitude, the cross sectional areas of adsorbed molecules. The adsorption enthalpies (isosteric heat of adsorption) were determined from adsorption isotherms at different temperatures. The surface orientations of the studied molecules were analyzed by MarvinSketch program. (doi: 10.5562/cca2343)