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Silver nanoclusters as fluorescent nanosensors for selective and sensitive nitrite detection

Chen, Chen, Yuan, Zhiqin, Chang, Huan-Tsung, Lu, Fengniu, Li, Zenghe, Lu, Chao
Analytical methods 2016 v.8 no.12 pp. 2628-2633
analytical methods, anions, biosensors, carcinogenicity, chemistry, detection limit, fluorescence, food preservatives, hydrogen peroxide, lakes, nanosilver, nitrites, pollutants, polyethyleneimine, seawater, tap water
As a highly carcinogenic pollutant but also an important food preservative, nitrite has attracted growing attention in the past few years. In this work, a hyperbranched polyethyleneimine protected silver nanocluster (hPEI-Ag NC) based nanosensor is proposed for the detection of nitrite. The sensing principle consists of two steps: nitrite reacts with hydrogen peroxide (H₂O₂) to generate peroxynitrous acid under acidic conditions, and the as-formed peroxynitrous acid then induces the aggregation and fluorescence quenching of hPEI-Ag NCs. Due to the specific nitrite–H₂O₂ chemistry, the hPEI-Ag NC based nanosensor shows high selectivity toward nitrite over other anions with a limit of detection of 100 nM. The practical application of the proposed nanosensor has been validated with lake water, tap water and seawater samples.