Digital videometrics analysis for the kinetic determination of dopamine in the presence of ascorbic acid based on the formation of silver nanoparticles

Abstract

A simple, cost-effective and rapid method for the visual detection of dopamine (DA) and ascorbic acid (AsA) based on the video-image analysis has been developed. The method is based on the formation of silver nanoparticles by the reaction of dopamine and/or ascorbic acid with silver nitrate. The video of the brown color produced during the reaction was recorded and then the framed images were extracted. Changes in the red, blue and green (RGB) elements of the images as a function of time produced kinetic profiles, which were very similar to the spectrophotometric study. Using fix-time analysis of the kinetic profiles, linear calibration curves were obtained for dopamine and ascorbic acid in the concentration ranges of 4.95 × 10⁻⁶ to 2.38 × 10⁻⁵ M and 9.80 × 10 ⁻⁶ to 7.63 × 10 ⁻⁵ M, with detection limits of 2.5 × 10⁻⁶ M and 3.10 × 10⁻⁶ M, respectively. Then, the imaging-based kinetic profiles were used for multicomponent analysis based on the partial least squares (PLS) and principal component analysis-artificial neural network (PC-ANN) models. This is the first attempt to use image analysis for the kinetic determination of dopamine in the presence of ascorbic acid with the aid of chemometrics methods. In this manner, the accurate determination of dopamine in the presence of ascorbic acid using very simple instrumentation was achieved. The root mean square error for the estimation of dopamine in the synthetic binary mixtures was about 6%.