(95d) Detection of arsenic in water using microfluidic based paper analytical device

The ever-expanding industrial sites and their disposal of arsenic containing compounds has become a major reason of concern towards our environment and human health. The consumption of arsenic contaminated water can cause major health issue such as skin cancer, kidney and brain damage. Due to these reasons, the monitoring of water quality has become progressively important and crucial. The importance of water quality monitoring could be realize by the number of literatures published in the last decade. Traditionally, the water sample are collected from various locations and are send to a well-equipped laboratory for sampling and analysis. Some of the analytical instruments include atomic absorption spectroscopy, fluorescence microscopy, turbidity meter, conductivity meter, and UV-vis spectrometer. However, these techniques will always call for the need of various analytical instruments and well-developed laboratories. In addition, with increased rate assisted with the diversity of pollutants in water bodies poses a massive challenge in monitoring huge geographical locations. Such situation demands the need to develop portable, inexpensive, as well as rapidly detecting miniature devices. These demands could be address by employing a microfluidic based paper analytical device (µPAD). Herein, we developed a µPAD for detecting of arsenic (As) in water by employing colorimetric technique. The fabrication of µPADs is achieve by employing the wax printing technique. In order to achieve selective detection of arsenic, the gold nanoparticles (AuNP) are functionalize by adding 5 ml of D-glucose at varying concentrations (0, 0.001, and 1 M) to 5 ml of AuNP. The gold nanoparticle is synthesize by chemical reduction of gold chloride solution and tri-sodium citrate. Next, we perform a UV-vis spectrometry and dynamic light scattering (DLS), in order to find the absorption spectra and particle size of the AuNP. The UV-vis spectra showed a characteristic absorption peak at ~520 nm. This is due to the surface plasmon resonance (SPR) property of AuNP. The attachment of D-glucose can be confirm by the decrease in the absorption intensity. While the DLS shows that the average size of AuNP is ~32 nm. Finally, the functionalized gold nanoparticles are embedded in the µPAD followed by drying in a vacuum desiccator. Next, sodium arsenite solution (0.1 M) is drop into the µPAD, which turned into a bluish-black precipitate demonstrating the binding of sensor with the arsenic solution.