QUIMICA ANALITICA, vol.19, pp.94-98, 2000 (SCI-Expanded)
Optical Cu(II) ion sensors, based on several reagents such as 1-nitroso-2-napthol (NN), 2,4-dinitrosoresorcinol (DNR), 4-(2-pyridylazo)resorcinol (PAR), 1-(2-pyridylazo)-2-naphthol (PAN), immobilized on a variety of polymeric materials such as XAD-4, XAD-7, and Dowex have been studied. A kinetic approach was used to determine the sensor response to Cu(II) concentration, where the reflectance signals measured after a fixed time were utilized. The relative standard deviations (%) attained with these sensors were satisfactory (RSD -0.97 - 1.15 %). Important parameters such as pH, measurement wavelength, and immobilized reagent concentration have been optimized. The pH dependence and complex formation constant of the Cu (II)-NN/XAD-7 complex have also been investigated along with important sensor characteristics such as, response time (1-4 min), linear range (0.5-20 ppm), detection limit (0.5-1.0 ppm), and sensor regeneration.