A novel highly sensitive zeolite-based conductometric microsensor for ammonium determination
Résumé
Natural zeolite clinoptilolite was successfully applied in the sensing technology for electrochemical detection of ammonium. A novel ammonium-selective sensor was developed based on clinoptilolite, possessing intrinsic ammonium-sieving and ion exchange capacity. The sensor design allowed measurements in both differential mode and requiring no classical reference electrode. The sensor selectivity towards Na+, K+, Ca2+, Mg2+, and Al3+ was studied. The limit of detection and the dynamic range of the ammonium-selective conductometric microsensor, determined in the phosphate buffer solution, were 1.0 x 10(-8) M and 0-8 mM, respectively. The ammonium sensor presented high operational and storage stability.