The Optimization And Study Of Ion-Selective Electrode Membranes

The optimization of two types of cation-selective membrane electrodes were studied in this dissertation. ETH1001 and ETH2120 were as ionophores to prepare Ca2+and Na+-selective membrane electrodes, respectively. Different plasticizers, polymers and additive were tested thought the potentiometric experiments. These electrodes that prepared with 2-Nitrophenyl-octylether (NPOE) as plasticizer showed better potentiometric response. In this case, a mixture of polymer (PU 37.5g and PVC 12g) used as matrix, as well as KTpClPB added to the membrane has shown better results. In the case of the optimized Calcium selective electrode based on ETH1001, the average response slope toward calcium was 28.8 mV/dec, and the selectivity coefficients (KCa2+,j pot) of the Sol-Gel membrane for Na+, K+, Mg2+and NH4+relative to Ca2+were 5.1,-4.9,-4.2 and-4.8 respectively. In the case of the optimized sodium selective electrode based on ETH2120, the average response slope toward calcium was 56.3 mV/dec, and the selectivity coefficients (KNa+,j pot) of the Sol-Gel membrane for Ca2+, K+, Mg2+and NH4+relative to Ca2+were-3.3,-1.6,-3.9 and-3.7 respectively.The Sol-Gel sensor membranes based on Co(TPP)Cl were prepared in this study. The membranes (contain 10%and 20%TDMAC) average response slopes toward NO2-were 50 and 54 mV/dec, respectively. The selective toward nitrite over other anions were tested by the separate solution method.