Prospects for the Use of Analytical Systems Based on Silver Triangular Nanoplates for the Spectrophotometric Determination of Reductants

Possibilities of using analytical systems based on silver triangular nanoplates for the spectrophotometric determination of reductants are studied. It is found that the interaction of silver triangular nanoplates with L-ascorbic acid in the presence of silver(I) nitrate is accompanied by a bathochromic shift and an increase in the intensity of the surface plasmon resonance band of nanoparticles, which can be used as the basis for methods for determining reductants. The proposed interaction mechanism includes the reduction of Ag + ions to metallic silver under the action of an analyte and its deposition on the surface of nanoparticle seeds. The effects of pH, interaction time, and concentrations of reagents and foreign compounds on the value of the analytical signal are studied. The limit of detection for L-ascorbic acid under the selected conditions is 0.5 mg/L, the analytical range is 1.7–60 mg/L. The approach proposed in this paper was applied to the determination of L-ascorbic acid in leafy green tea and apple juice.