The detection of some metal ions has been investigated using an optical sen
sor based on surface plasmon resonance (SPR). A multilayer sensing chip was
prepared with a dithiosquarylium (DTSQ) dye sensing layer coating on a gol
d layer. Using the DTSQ dye as a metal ion sensing molecule, a highly selec
tive response for Ag+ was observed. (C) 2000 Elsevier Science Ltd. All righ
ts reserved.