Dual-channel colorimetric sensor based on metal ion mediated color transformation of AuNPs to identify the authenticity and origin of Atractylodis Macrocephalae Rhizoma

Atractylodis Macrocephalae Rhizoma (AMR) is a bulk herbal foods, which can invigorate spleen and supplement Qi to help health. The accurate identification of the authenticity and origin of AMR is a prerequisite for the safe use and quality control. Herein, a dual-channel colorimetric sensor based on metal ions mediated color transformation of gold nanoparticles (AuNPs) was constructed to identify the authenticity and origin of AMR. The Ag+ / cetyltrimethylammonium chloride modified AuNPs (CTAC-AuNPs) sensing channel and Cr3+ / trisodium citrate modified AuNPs (TCA-AuNPs) sensing channel were rationally designed based on two mechanisms that are the silver deposition and the induced aggregation, respectively. When AMR extracts from different origins or its counterfeits were added to the colorimetric sensor, significantly different terpenoids in extracts can bind to Ag+ or Cr3+ to produce different color transformations. AMR samples from three origins (Zhejiang, Hunan and Anhui) and the counterfeit samples (Gynura japonica (Thunb.) Juel., and Atractylodis Rhizoma) were all accurately classified using the dual-channel colorimetric sensor combined with PLSDA. Our sensor has obvious advantages of simple and instrument-free analysis procedure, which will provide a new idea for the convenient identification of AMR and other herbal foods.