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Inorganic components have been widely applied as geographical traceability biomarkers of plant derived food and phytophagous insects. Helicoverpa armigera (H. armigera) (Lepidoptera: Noctuidae), a global economic pest, has been shown to be able to migrate long distances but the detailed migration paths are still unclear. Herein, the levels of 10 minerals (Mg, Al, K, Ca, Mn, Fe, Cu, Zn, Cr and Sr) in 32 H. armigera adults from different growing backgrounds were evaluated by inductively coupled plasma – optical emission spectrometry (ICP-OES). The discrimination of these insects from five groups was realized by using principal component analysis (PCA) and canonical discriminant analysis (CDA). The results showed that H. armigera from different growing backgrounds discriminated by PCA and CDA achieved high accuracy values of 84.4% and 100.0%, respectively. Additionally, cross-validation was utilized to check the confidence of the CDA results with an accuracy of 81.3%. The present study shows that geographical discrimination established by chemometric analytical methods achieves high confidence in terms of the identification of the phytophagous insect H. armigera. The application of this pattern may contribute to resolving migratory insect issues in the near future. [ABSTRACT FROM AUTHOR]

Novel core-shell molecularly imprinted polymers were prepared based on zinc oxide quantum dots for the determination of 2,4,6-trichlorophenol by fluorescence. Principally, ZnO quantum dots and 2,4,6-trichlorophenol were chosen as the core substrate and the template molecule, respectively. The specific recognition sites for 2,4,6-trichlorophenol were obtained during the polymerization process in presence of 3-aminopropyltriethoxysilane and tetraethylorthosilicate. Molecularly imprinted ZnO quantum dots were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy and the optical properties were evaluated by spectrofluorometry. Under the optimal conditions, molecularly imprinted ZnO quantum dots were successfully applied to the sensitive determination and selective recognition of 2,4,6-trichlorophenol in water. A linear relationship was obtained to cover the concentration range of 0-160 µmol L−1 with a correlation coefficient of 0.9931 calculated by the Stern-Volmer equation. The products were used for the determination of 2,4,6-trichlorophenol in the water from local rural areas and the results strongly supported that the molecularly imprinted ZnO quantum dots were suitable for the determination of 2,4,6-trichlorophenol in real examples. [ABSTRACT FROM AUTHOR]