Membrane composition effects on the analytical behavior of solid contact potentiometric pb2+ selective electrodes based on diazadibenzo-18-crown-6 ionophores

摘要

The effect of component contents and membrane thickness on the detection limit (DL), slope (m), linear range (LR) and response time (RT) of Pb2+ solid contact potentiometric ion selective electrodes (SCISE) based on 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (1), 4,10-diaza-2,3,11,12-di(4-tert-butylbenzo)-18-crown-6 (2) and 4,10-diaza-2,3,11,12-dibenzo-18-crown-6-N,N'-di(carboxymethyl) (3) as ionophores was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) measurements. The use of an intermediate layer of poly(3-octyl)thiophene between the gold substrate and the selective membrane was explored. SCISE prepared showing the best responses had typical DL, m, LR and RT values of 10-6M, 29mV/dec, 10-5 to 10-3M and 2 minutes.