As(III) determination is of great importance in various industries such as environmental monitoring, pharmaceuticals, and metallurgy. In this respect, a nanocomposite of sucrose-modified gold nanoparticles (Au@Suc) was synthesized and characterized by UV-visible spectrophotometry and transmission electron microscopy (TEM) methods. Then, the applicability of the synthesized nanocomposite for the development of a microfluidic kit for the colorimetric point-of-care (POC) detection of As(III) ions was scrutinized. 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-1, 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 µM, with a detection limit of 0.054 µM. 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%.
