The present invention relates to a chemical sensor arrangement having an analyte sensitive indicator wherein the analyte sensitive indicator has at least one nanoparticle. The invention further relates to a method for providing nanoparticles of defined and different sizes, especially for a chemical sensor arrangement, wherein a nanoparticle solution, having nanoparticles of a broad size distribution, is applied to chromatography beads, whereby the nanoparticles are adsorbed onto said beads and classified by size, and beads of a specific layer, having nanoparticles of essentially the same size, are separated from the beads within other layers and are held in suspension.