In a composite structure, which contains dielectric-metal interface, waves of electric charge densities can be initiated. The wave intensity decreases exponentially in adjacent media meaning that the wave closely localized at the interface does exist. Label-free chemical sensors are realized as the propagation constant of the wave is highly sensitive to the refractive index. Surface plasmons can be excited by incident light flow directed at some specific angle (surface plasmon resonance) with a very sharp shape. In the present paper the possibility of identification of several most common alcohols such as methanol, ethanol, propanol, butanol, or pentanol, which have different refractive indices, has been studied. The structure is composed of a coupling prism made of rutile (TiO 2 ), a thin gold film, and an amorphous arsenic sulfide (As 2 S 3 ) thin film.