Copper nanoparticles: A new colorimetric probe for quick, naked-eye detection of sulfide ions in water samples

This study introduces a new method for the visual and spectrophotometric detection of chemical species using copper nanoparticles (Cu NPs). A simple method for the synthesis of Cu NPs for rapid colorimetric visual detection of sulfide ions (S2−) in water samples is described. The Cu NPs sensor detects sensitive and selective color change in the presence of micromolar levels of S2− that can be observed with the naked eye and monitored using a UV–vis spectrophotometer. The color change quantitatively correlates with the concentration of S2− from 12.5×10−6 M to 50.0×10−6 M. Samples of tap water and river water were spiked and analyzed using the proposed system. The results showed that the sensor exhibited excellent detection for S2− in the water samples. A main advantage of the new method is that it provides good selectivity for detecting S2− without the need for complex readout equipment. The proposed method has a high potential for rapid environmental monitoring of sulfide ions.