We report a colorimetric system for the detection of HCl in aqueous environments using unlabeled gold nanoparticle (AuNP) probes. This nonaggregation-based detection system relies on the ability of chloro species to cause rapid leaching of AuNPs in an aqueous dispersion containing a strong oxidizing agent, such as HNO 3 or H 2O 2. The leaching process leads to remarkable damping of the surface plasmon resonance peak of the AuNP dispersion. This method works only with AuNPs of a particular size (∼30 nm diameter). It is highly selective for HCl over several common mineral acids, salts, and anions. This simple and cost-effective sensing system provides rapid and simple detection of HCl at concentrations as low as 500 ppm (far below the hazard limit) in natural water systems.
ASJC Scopus subject areas
- Analytical Chemistry