Silver nanoparticles and Griess reaction in determination of bisphenol A

In this work, we introduced two colorimetric methods to determine Bisphenol A (BPA) in water samples using silver nanoparticles (AgNP) prepared by walnut carbon dot and Griess reaction. Therefore, firstly the optimal medium was selected based on acidic, neutral and alkaline media. In determination by AgNPs, the optimal order of addition of the reagents was obtained as: sample containing BPA, sodium hydroxide and AgNP. In the presence of 100 microliter of synthesized AgNPs, the highest variation in the AgNP spectrum while BPA is added was observed. In the presence of BPA, the yellow color of AgNP is faded. In this method, a linear range of 1.0–16.0 ppm and LOD of 0.68 ppm was obtained. In Griess method, nitrite and 2-nitroaniline were used as reagents and BPA act as analyte. In the method, for reaction and observing the color, sample containing BPA was added to the reaction mixture (nitrite and 2-nitroaniline with concentrations of 0.60 M and 0.072 M, respectively). Response surface methodology was used to investigate the Griess reaction. According to the results, the lower the concentration of 2-Nitroanilin and the higher the concentration of nitrite the better the response and the clearer the color change. With Griess reaction, linear range and LOD were 3.0–25.0 ppm and 0.65 ppm of BPA, respectively. Real water sample and spiked samples were analyzed by proposed method which results were satisfactory.