SPR sensor with matrix arrangement of nanostructured golden spots enables both the study of low concentrations of substances in solution and the acquisition of information on the spatial layout of the diagnosed medium in solution. The linear response of this sensor was experimentally specified for standard solutions of alcohols in a concentration range of 0.01 - 0.5 wt%. The influence of signal noise generated by carrier substance flowing through sensing dots has been removed by data processing. This approach enables to determine refractive index changes less than 3 × 10-6.