Binding of pyrene probe cation of 1 pyrenemethylamine hydrochloride(PyMeAH +) to sulfonate polyelectrolyte PAMPS in aqueous solution was investigated by the relative fluorescent intensity I E/ I M of the excimer to monomer. The saturation amount of repeat unit AMPS for the polyelectrolyte bound to one PyMeAH + ion was about 2 5 estimated from the maximum on the curve of I E/ I M vs. the probe concentrations. The increase of the ionic strength of the solution by adding salt or excess alkali ions of 10 -4 mol/L greatly reduced the I E/ I M value. This fact suggested that the probe cation PyMeAH + form a loose ion pair with the sulfonate anion on the polyelectrolyte.
