Detection of Mercury in Water using Filter Paper Based Channel and Colorimetric-Android Readout

Abstract

The heavy metals dissolved in water are exceptionally unsafe to human and marine health which causes numerious medical complications. This paper demonstrates the use of a Microfluidic paper-based channel (µPAD) and an easyto-use colorimetric android based application for the accurate detection of heavy metal Mercury (Hg2+) in water. Gold Nanoparticles (AuNPs) functionalized with Papain and 2,6- pyridinedicarboxylic acid is used to detect Hg for further colorimetric analysis. Droplet-based Microfluidic channel in star shape with a paper-based stencil, a hydrophobic barrier and a hydrophilic channel using Polyvinyl Alcohol (PVA) was created for this. Colorimetric detection is used to create a database which is used to calibrate the color range for other unknown quantities of Mercury (Hg2+ ) present in water. This experimental database was used to create a user-friendly Android Application based display. The real-time android application was calibrated to quantify mercury concentrations from 0.1g / Litre to 0.001mg / Litre by observing a change in color from red to blue. This built platform can be utilized as a basic low-cost and portable system for various other fluid testings.