Development of a Colorimetric Paper Sensor for Hg(2+) Detection in Water Using Cyanuric Acid-Conjugated Gold Nanoparticles

Hg(2+) is one of the most dangerous pollutants that can cause damage to organs and the immune system. The common detection methods of Hg(2+) require sophisticated instrumentation and a long time for analysis. The purpose of this study was to develop a sensor for the detection of Hg(2+) using filter paper immobilized by gold nanoparticles (AuNPs) conjugated with cyanuric acid (CA). The clear color change from pink to bluish purple is the response of the CA-AuNPs filter paper sensor to exposure to Hg(2+). Detection can be observed visually with the naked eye and/or with imageJ software; the detection limit is 0.05 µM. The colorimetric response of the sensor was also selective towards Hg(2+) after testing with different metal ions. In addition, the response from the sensor was also consistent for lake water samples spiked with Hg(2+). The results of this research provide a promising basic technology for the development of sensors that are affordable, fast, portable, and easy to use for the detection and monitoring of Hg(2+) levels in water.