Resumo

ARADA-PEREZ, María de los Ángeles et al. Nitrate determination in natural water samples by potentiometry with ion selective electrode. Rev Cub Quim [online]. 2022, vol.34, n.2, pp. 242-262.  Epub 14-Jun-2022. ISSN 2224-5421.

In this work, a nitrate selective polymeric liquid membrane electrode was evaluated in real samples using diethylphthalate (DEP) as plasticizer, trioctyl methyl ammonium chloride (ClTOMA) as ionophore and polyvinyl chloride (PVC) as matrix, on a conductive support. The constructed electrode showed a fast potentiometric response to nitrate ion in the concentration range 10-6 to 10-2mol ∙ L-1, with an overnernstian slope of -70,14 ± 1,93 mV ∙ dec-1. Sensor membranes reported in the literature made up of the same ionophore and matrix were compared with the DEP being the one with the highest sensitivity due to its higher electrode response slope value. The measurement uncertainty was estimated under conditions of intermediate precision of the analysis for 95 % confidence at three concentration levels with values of 10 % for contents less than 10 mg ∙ L-1, 5,9 % for contents close to 40 mg ∙ L-1 and 5,1 % for contents greater than 80 mg ∙ L-1.

Palavras-chave : nitrate ion selective PVC membrane; ion selective electrode (ISE); triocthylmethylammonium chloride (TOMACl); expanded uncertainty.

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