Surface plasmon resonance study for detection of ethanol in water and moisture content of hevea latex

Abstract

Surface plasmon resonance was used to detect ethanol in water and the moisture content of hevea latex. The apparatus consists of a thin gold film deposited onto a surface of a 60° cube prism, while the film-free surface remains in contact with the sample throughout the measurement. The reflectance of the samples of various concentrations were measured as a function of incident angle, by rotating the sensing prism assembly. When the moisture is sufficiently low, a further shift of the resonance angle with the time is observed. The initial rapid variation of the resonance angle with time is due to the coagulation process in the gold surface.