A Rapid Visual Detection of Ascorbic Acid Through Morphology Transformation of Silver Triangular Nanoplates

A rapid and sensitive colorimetric detection of ascorbic acid (AA) through the morphology transformation of silver triangular nanoplates (Ag TNPs) is developed. By virtue of the redox reaction among silver nitrate and AA, the newly formed Ag atoms deposited on the surfaces of Ag TNPs. Subsequently, the morphology of Ag TNPs transforms from triangle to circle, resulting in a more than 160 nm blue shift of localized surface plasmon resonance absorption peak. The corresponding color of the solution converting from blue to yellow with the concentration of AA can be observed by naked eyes within 15 min. A linear relationship between the blue shift of absorption peak and the concentration of AA ranging from 0.2 to 6 μM is obtained with a limit of detection (LOD) of 100 nM (3 σ ). Some potential species (e.g., glucose, urea and various amino acids) coexisting in the system showed little or no interference. The proposed assay is successfully employed to determine the amount of AA in pharmaceutical products with recoveries from 96.9 to 106.5% and offers a sensitive, low-cost, rapid and simple assay of visual analysis of ascorbic acid.