Abstract: Based on surface plasmon resonance(SPR), a novel optical chemical sensor was developed. Traditionally SPRsensing method was to fix wavelength and modulate angle of incidence light, which needed an expensive and complicated apparatus. The device presented here is a relatively simple and inexpensive. It was designed on the basis of fixing angle of incidence light in the range of the wavelength of 400～800 nm. The reflected light intensity is the minimum at the resonant wavelength, a smaller increase in refractive index of the analyzed solution would cause a clear shift in the SPRreflection spectra toward larger resonant wavelength. The sensitivity to refractive index changes was found to be 4.6×10^-4index of refraction units at a wavelength of 575 nm. Some sample were analyzed with the sensor. The results obtained are in good agreement with those obtained with other method. Under the selected experimental conditions, the sensor has a good repeatability(RSD≤1.4).

Key words: Surface plasmon resonace, Optical chemical sensor, Alcohol