A renewable copper electrode as an amperometric flow detector for nitrate determination in mineral water and soft drink samples |
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Authors: | Juan CM Gamboa Thiago RLC Paixão |
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Institution: | a Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-900, Brazil b Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP 09210-170, Brazil |
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Abstract: | A novel approach was developed for nitrate analysis in a FIA configuration with amperometric detection (E = −0.48 V). Sensitive and reproducible current measurements were achieved by using a copper electrode activated with a controlled potential protocol. The response of the FIA amperometric method was linear over the range from 0.1 to 2.5 mmol L−1 nitrate with a detection limit of 4.2 μmol L−1 (S/N = 3). The repeatability of measurements was determined as 4.7% (n = 9) at the best conditions (flow rate: 3.0 mL min−1, sample volume: 150 μL and nitrate concentration: 0.5 mmol L−1) with a sampling rate of 60 samples h−1. The method was employed for the determination of nitrate in mineral water and soft drink samples and the results were in agreement with those obtained by using a recommended procedure. Studies towards a selective monitoring of nitrite were also performed in samples containing nitrate by carrying out measurements at a less negative potential (−0.20 V). |
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Keywords: | Nitrate Nitrite Flow injection analysis Renewable copper surface Mineral water Soft drink |
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