Supramolecular fluorescent sensor array for simultaneous qualitative and quantitative analysis of quaternary ammonium herbicides†
The quaternary ammonium herbicides mainly include paraquat and diquat, whose fast and simultaneous detection is important for environmental and public safety. Herein, we simultaneously analyzed paraquat and diquat by a simple three-component supramolecular sensor array, which was simply prepared from carboxymethyl-β-cyclodextrin (CM-β-CD) and fluorophores. Under the optimal pH, the two herbicides were excellently distinguished in the principal component analysis (PCA) score plot in the presence of various interferences. Then, the results of semi-quantitative analysis through linear discrimination analysis (LDA) also showed good cluster separation for both paraquat and diquat in the concentration range of 10–250 μM. Moreover, in order to test the unknown samples, the support vector machine (SVM) regression model was applied for simultaneous quantitative analysis of paraquat and diquat, which was successful in the prediction of the amount of the two analytes. Accordingly, this simple supramolecular sensor array is expected to be applied in the rapid and accurate analysis of quaternary ammonium herbicides.