Development of a Low-Cost Microfluidic Kit for the Smartphone-Based Colorimetric Determination of As(III) in Drinking Water Samples

As(III) determination is of great importance in various industries such as environmental monitoring, pharmaceuticals, and metallurgy. Therefore, we successfully synthesized and characterized a nanocomposite of sucrose-modified gold nanoparticles (Au@Suc) using UV-visible spectrophotometry and transmission electron microscopy (TEM), in this research. The use of a nanocomposite enabled the development of a microfluidic kit for the colorimetric point-of-care (POC) detection of As(III) ions. The experimental parameters for the microfluidic kit were optimized using the one-factor-at-a-time (OFAT) approach. The effective conditions for the microfluidic kit were found to be a flow rate of 0.15 ml/min, a path length of 5.50 cm, and a pH of 7.0. The resulting microfluidic kit indicated a direct correlation between the red component of RGB pixels in images captured by a smartphone and the concentration of As(III) ions in the range of 0.09-1.20 µmol L-1, with a detection limit of 0.054 µmol L-1. Evaluation of the microfluidic kit's selectivity revealed no significant interference. Additionally, the microfluidic kit was successfully employed to analyze As(III) in various drinking water samples, with recovery values ranging between 95.01% and 105.00%.