A new version of AgFON substrates for high-throughput analytical SFRS applications

The drop coating technique was applied to generate thin films of various polymer nanospheres as a basis for the preparation of AgFON (Ag films over nanospheres). In contrast to the well known spin coating technique, the chosen procedure also allows the use of multiwell (microtiter) plates as substrate, thereby opening up the possibility of a high-throughput analysis technique based on SERS. Employing commercially available spheres of polystyrene (diameter 533 nm) or silica (diameter 470 nm) and an Ag top layer 200 nm thick, SERS spectra of several food dyes were recorded; for Brillant Green (E 142), the detection limit was about 500 pg per well. Copyright (C) 2002 John Wiley Sons, Ltd.