Potassium-selective optical microsensors based on surface modified polystyrene microspheres.

Ion-selective microspheres based on surface modification of polystyrene particles (0.8 and 2.4 μm, diameter) are presented here for the first time. The traditional lipophilic sensing components of K(+) selective optodes (chromoionophore, ion-exchanger and ionophore) are adsorbed on the surface of the polystyrene particles using a simple mixed solvent method. The resulting microparticles respond to K(+) in an exhaustive sensing mode with excellent selectivity and rapid response time (t95% = 5 s).