RESUMEN
3D nanocake-like Au-MXene and Au pallet (Au-MXene/AuP) nanocomposite-modified screen-printed carbon electrodes (SPCEs) were utilized to construct an ultrasensitive label-free electrochemical aptasensor through a self-assembly procedure for trace paraquat (PQ) residue detection. Benefiting from the excellent electrochemical (EC) performances (e.g., high conductivity and large surface area) of Au-MXene nanocomposites and AuP substrate, the developed Apt/Au-MXene/AuP/SPCE-based EC aptasensor displayed excellent specificity and anti-interference ability, good repeatability, and stability. A linear relationship between the log value of the change in current intensity [lg (ΔI)] and the log value of the concentration of PQ [lg (CPQ)] was obtained in the range 0.05-1000 ng/mL. The limit of detection was 0.028 ng/mL, and the sensitivity was 255.5 µA/(µM·cm2). Practical applications in malt and mint samples confirmed the accuracy of the EC aptasensor in complex matrices for PQ detection, providing a universal analytical tool for other trace pesticides in different food samples by simply replacing the corresponding aptamers.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Límite de Detección , Técnicas Electroquímicas/métodos , Paraquat , Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Oro/químicaRESUMEN
OBJECTIVE: To study the water soluble constituents from Amomum villosum. METHOD: The constituents were separated and purified with chromatographic methods, identified by NMR, MS, UV and IR. RESULT: Two quercetin glycosides: quercitrin (quercetin-3-O-alpha-L-rhamnoside I) and isoquercitrin (quercetin-3-O-beta-D-glucoside II) were isolated and identified. CONCLUSION: I and II were isolated for the first time from A. villosum.