A Colorimetric Sensor Array Based on Ag Deposition on the Surface of Au/Ag Nanoparticles for accurately Discrimination of Baijiu

Baijiu plays an essential role in Chinese food culture, but there are still certain limitations in the identification of the aroma type and brand of Baijiu. In this study, based on the Tollen’s reagent, a colorimetric sensor array was constructed for aldehydes and Baijiu discrimination. In the presence of aldehydes or Baijiu, the silver ions (Ag + ) adsorbed by negatively charged nanoparticles can be reduced to elemental silver (Ag 0 ) in situ. Ag 0 deposited on the surface of gold or silver nanopaticle (Au NPs or Ag NPs) leading to the formation of Au@Ag or Ag@Ag core-shell structure which accompanied by a color change. We developed Tollen’s reagent-based sensor array shows the outstanding detection capability in discriminating and quantifying of aldehydes. On this basis, 16 kinds of Baijiu were also identified accurately, the visual results were verified by HCA and LDA models. The colorimetric sensor developed in this study is promising for aroma recognition and brand identification of Baijiu.