Gold nanoparticles-decorated paper-based sensor for rapid cyanide detection in water

Abstract

In this study, a versatile sensing platform based on a commercially available filter paper for the development of a colorimetric sensor using label-free gold nanoparticles (AuNPs) for the detection of cyanide in water is presented. The developed sensor can be applied for the direct detection of cyanide from an aqueous sample efficiently in a wide concentration range. The synthesised AuNPs were found to have an average size of about 13.2 ± 2.65 nm with a surface plasmon resonance peak at around 525 nm. Successful integration of AuNPs on the WFP substrate was observed through the FESEM-EDX analysis and supported by the presence of an absorbance peak at about 528 nm on the spectrum of the WFP-AuNPs composite. The colour of the WFP-AuNPs composite changed from purple-red to white in the presence of cyanide. Using the paper-based sensor, the limit of detection is calculated to be 7.68 × 10−6 M (0.5 ppm). The said sensitivity is good enough for the determination of cyanide in industrial wastewater samples. The developed sensor also showed excellent selectivity towards cyanide over other ions, demonstrating its practical applicability to monitor cyanide contamination in different environmental samples. Furthermore, the applicability of the sensor was demonstrated using several real water samples spiked with cyanide, including creek and tap water. Notably, the sensor showed great promise for the rapid, cost-effective, and versatile monitoring of cyanide contamination in various aqueous samples.