Puerarin-coated gold nanoparticles (PUE-AuNPs) synthesized via green synthetic route: a new colorimetric probe for the detection of ciprofloxacin

Puerarin-coated gold nanoparticles (PUE-AuNPs) synthesized via green synthetic route, a new colorimetric sensor, efficiently detected the ciprofloxacin (CP) in tap water and cow milk samples. The PUE-AuNPs were characterized by UV-visible, FTIR, AFM, and DLS techniques and were found to be spherical with an average size of approximately 19–20 nm. FTIR spectrum confirms that functional groups such as –OH, -C=O, -CO and –C=C were responsible for the reduction of gold (III) chloride trihydrate. These functional groups acted as capping agents to form AuNPs. The PUE-AuNPs sensor was proved to be selective and sensitive for the detection of CP through colorimetric method within the concentration of 1 to 1000 µM and the limit of detection was 51 µM. This colorimetric sensor is simple, cost-effective, and selective towards CP detection in environmental (tap water and milk) samples.