Adsorbate enrichment on a zeolite surface and assembly of a SERS sensor: a case study with silver nanoparticles and the flavonoid catechin.

We have studied the adsorption of silver nanoparticles (AgNPs) and catechin on readily available commercial zeolite beads. Both adsorbates became available on the zeolite and were several fold more concentrated after a simple adsorption process, contributing to a 10-times overall increase in the collision probability between the two adsorbates. We were further able to detect AgNP-induced Surface Enhanced Raman Scattering (SERS) of catechin on the zeolite after sequential depositions of AgNPs and catechin on the zeolite using this process. To demonstrate high reproducibility, 93% of the zeolite sensors assembled this way were tested and proved satisfactory, and gave a distinctive catechin SERS signature. Preparation of the zeolite sensor was extremely easy with a nearly 90% yield.