Yiqian Kong,Zongyi Li,Qi Liu,Juncheng Song,Yinghua Zhu,Jinping Lin,Lili Song,Xiangyang Li
In this work, V 2 C Mxene nano-enzyme materials (V 2 C MNs) with excellent peroxidase-like activity and fluorescence quenching performance were prepared, and it was modified using 6-carboxyfluorescein-labelled aptamers (ssDNA-FAM) to construct a novel dual-mode sensor V 2 C@ssDNA-FAM, with detection limits of 0.0477 ng mL −1 and 0.2789 ng mL −1 of fluorescence (linear range of 0.1–550 ng mL −1 ) and colorimetric (linear range of 1–1000 ng mL −1 ) modes, respectively. Meanwhile, an ANN intelligent detection platform has been constructed, which could automatically track and analyze the fluorescence and colorimetric signal of the detection system through machine learning and immediately obtain the AFB 1 concentration, and the detection limits of the fluorescence (linear range of 0.1–500 ng mL −1 ) and colorimetric (linear range of 1–800 ng mL −1 ) channels of it were 0.0905 ng mL −1 and 0.6845 ng mL −1 , respectively. The recovery rates of fluorescence, colorimetric sensing detection and ANN-assisted fluorescence and colorimetric sensing detection of real samples ranged from 95.40% to 101.76%. The method constructed in this work was superior to most existing literature reports and had great potential for application in the field of food quality testing.
A novel electrochemical sensor was constructed based on an overoxidized polypyrrole/overoxidized poly(3,4-ethylenedioxythiophene)/graphene quantum dots-chitosan composite film modified glass carbon electrode (oPPy/oPEDOT/GQDs-CS/GCE), for the accurate determination of luteolin in peanut shells. The oPPy/oPEDOT/GQDs-CS/GCE was prepared using layer-by-layer assembly methods. After incubation in NaOH–EtOH solution, the current of luteolin on the composite electrode increased from 0 to ∼30 μA, the Rct value decreased by ∼80 fold, and the specific surface area (A) increased by ∼7 fold. Based on a three-level four-factor Box–Behnken design (BBD), the optimal preparation conditions for the composite electrode were as follows: a mass ratio of CS to GQDs of 5, a polymerization cycle number for EDOT of 4, a polymerization cycle number for Py of 4, with the peak current increased to 43.21 μA (RSD = 3.51%, n = 3). A morphology with multi-channels and grooves was observed on the surface of the incubated composite film via SEM analysis. The additional –CN– and –SO/–SO2 groups formed were observed by XPS and FTIR analysis. The electrochemical sensor constructed exhibited good anti-interference ability, repeatability, and stability. The linear detection range recorded by the current responses of the composite electrode to luteolin was 0.01 to 10.0 μM (R2 = 0.991) and the limit of detection was 7.5 nM (S/N = 3). The observed content of luteolin in peanut shells was 0.769%, which was close to the results obtained from High Performance Liquid Chromatography (HPLC) analysis (0.808%). This agreement indicated that the constructed electrochemical sensor based on oPPy/oPEDOT/GQDS-CS/GCE was capable of accurate detection of luteolin in peanut shells.
危险品化学品经营许可证（带存储）