Electrochemical sensor for sensitive determination of nitrite based on the PAMAM dendrimer-stabilized silver nanoparticles

Silver nanoparticles stabilized by PAMAM dendrimer were synthesized by a simple chemical reduction method. By this method, stable and well-distributed silver nanoparticles were formed due to the abundant terminated groups of PAMAM. Based on the Ag-PAMAM nanocomposite, a novel electrochemical sensor for the determination of nitrite was constructed. The Ag-PAMAM modified electrode exhibited excellent electrocatalytic performance for the oxidation of nitrite. The effects of pH and applied potential on the current response of Ag-PAMAM modified electrode toward nitrite were optimized to obtain the maximal sensitivity. In pH 6.0 phosphate buffer solution, the sensor displayed a wide linear range from 4.0 μM to 1.44 mM. Moreover, the sensor had the advantages of high sensitivity (265 μA mM−1 cm−2) and short response time (3 s). The detection limit was estimated to be 0.4 μM. Furthermore, the practicality of the proposed sensor for the determination of nitrite was achieved in tap water and milk sample.