A highly sensitive method for the detection of p-Aminophenol based on Cu-Au nanoparticles and KIO₃

As a common industrial raw material and chemical intermediate, p-Aminophenol (pAP) is recognized as a serious pollutant that poses harm to both the environment and human health. The traditional detection methods for pAP have the advantages of good selectivity and high sensitivity, but their complex operation and time-consuming defects limit their application in on-site detection. Therefore, it is necessary to develop a simple, low-cost, rapid and high-sensitivity method for the detection of pAP.

Noble metal nanoparticles have been widely used in colorimetric sensing because of their simplicity and practicality. Herein, we presented a simple, excellent sensitive and selective colorimetric method for high-performance detection of pAP based on Cu-Au nanoparticles (Cu-Au NPs) and KIO₃. In the presence of pAP, KIO₃ was reduced to I₂, which subsequently chemically adsorbed onto Cu-Au NPs surface and induced the dispersion and reorganization of Cu-Au NPs, along with prominent color change of the dispersion from gray-blue to pink and the transformation of Cu-Au NPs from chain-like aggregates to individual dispersed, irregular, subspherical nanoparticles. The mechanism was verified by TEM, DLS, Zeta potential, UV-vis and XPS. Meanwhile, Cu-Au NPs probe can rapidly detect pAP within 25 min, the limit of detection of pAP probe is 5 μM by the naked eyes and 0.03 μM by UV-vis absorption spectrum.

This is the first colorimetric assay for pAP based on Cu-Au NPs probe. The satisfactory linearity (R² = 0.9984) indicates that the colorimetric probe based on Cu-Au NPs and KIO₃ can be utilized for quantitative detection of pAP. The detection results of pAP in real environmental water samples, urine samples and paracetamol tables demonstrate the practicability of pAP colorimetric probe.