Ammonium Determination in Water Samples by Using Opa-Nac Reagent: A Comparative Study with Nessler and Ammonium Selective Electrode Methods |
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Authors: | Susana Meseguer-Lloret Carmen Molins-Legua Pilar Campins-Falco |
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Affiliation: | Department de Química Analítica, Facultad de Química , Universitat de Valencia , C/Dr. Moliner 50, Burjassot, Valencia, E46100, Spain |
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Abstract: | A selective and sensitive method based on the ammonium derivatisation with o -phthaldialdehyde (OPA) and N -acetyl-cysteine (NAC) has been developed for ammonium determination in real water samples. The proposed procedure has been compared with ammonium reference methods such as Nessler reagent method and ammonium selective electrode. All procedures have been chemometrically tested and compared in terms of the main analytical properties. These procedures have been used to determine ammonium in unknown water samples. The OPA-NAC reagent method does not present any systematic error (proportional or constant), while Nessler reagent presents both of them for some samples assayed. The ammonium selective electrode is free of corrigible systematic errors, however presents amine interference. The OPA-NAC ammonium method is able to achieve a detection limit (LOD) of 0.07 mg/L in the sample, with a linear dynamic range up to 1.4 mg/L of ammonium. |
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Keywords: | Ammonium Opa-NAC Reagent Real Water Samples Nessler Method Selective Electrode Method |
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