The technology of fabrication of anion-selective light-addressable potentiometric sensors (LAPS) by using a solid-state microelectronic device integrated with an ion-recognition membrane has been elaborated. The nitrate sensor with ion-exchange membrane exhibits a linear response interval of 3 × 10-5 to 1 × 10-1 mol/l NO3- with an ionic sensitivity of 58 ± 2mV/pNO3. The detection limit was found to be 1 × 10-5 mol/l of nitrate ions and the working pH interval of the sensor is 2.0-11 for 10-2 mol/l NO3-. The sensor has a high selectivity for nitrate over chloride, sulphate, hydrogen phosphate and acetate ions with selectivity coefficients, KNO3/X, of 7 × 10-3, 1 × 10-3, 2 × 10-4 and 5 × 10-3, respectively, and a response time of about 1 min. The SO4-LAPS with polymeric membrane containing neutral sulphate ionophore demonstrates a sensitivity of 26 ± 1 mV/pSO4 in a concentration range of 3 × 10-6 to 1 × 10-2mol/l with a reasonable selectivity over chloride, hydrogen carbonate and hydrogen phosphate ions. Selectivity coefficients, KSO4/X, were found to be 0.6, 0.15 and 0.03, respectively.
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