Herein, we designed and synthesized a hybrid material
comprising
polystyrene submicrobeads coated with silver nanospheres. This material
provides a dense collection of electromagnetic hot spots upon illumination
with visible light. The subsequent coating with a metal-framework
and the adsorption of bathocuproine on it yield an optical sensor
for SERS that can specifically detect Cu(II) in a variety of aqueous
samples at the ultratrace level. Detection limits with this method
are superior to those of induced coupled plasma or atomic absorption
and comparable with those obtained with induced coupled plasma coupled
with a mass detector.