Carbon electrodes unmodified and decorated with silver nanoparticles for the determination of nitrite, nitrate and iodate

The determination of nitrate and iodate was carried out in samples of mineral water and iodized salt by electrochemical reduction at silver nanoparticles (AgNPs)-modified electrodes. AgNPs were deposited by conventional potentiostatic reduction of a AgNO3solution on flexible pure graphite sheets (PGS) and glassy carbon (GC). The analytical performances of the electrodes based on PGS were comparable to those of modified GC. The novel material can be considered an alternative to the more common glassy carbon. By adding ammonia to the electrodeposition solution it was possible to overcome the problem of Ag+ adsorption on the electrode surface which caused high background currents and prevented measurements in samples with high concentration of Cl-anions. Nitrite determination by oxidation was not feasible on the AgNPs-modified supports, thus this analyte was detected at bare PGS and GC.