Gold nanoparticles based digital color analysis for quinidine detection

In this contribution, we developed a novel digital color analysis of gold nanoparticles (AuNPs) for pharmaceutical detection by choosing quinidine as an example. It was found that the color of AuNPs colloid solution changed from red to blue in the presence of different concentrations of quinidine, and the color information of each solution could be digitalized with tricolor (RGB) system. Under the optimum conditions, the R value of the solution was found to be linear with the natural logarithm of concentration of quinidine in the range of 112-384 nmol/L. This method has the advantages of rapid, economical and simple, and can serve as a potential alternative to traditional spectrophotometry for practical use.