Anchoring Metallic MoS₂ Quantum Dots over MWCNTs for Highly Sensitive Detection of Postharvest Fungicide in Traditional Chinese Medicines

Abstract

Carbendazim, a very common contamination to the traditional Chinese medicines (TCMs), has posed serious threat to the environment and human health. However, sensitive and selective detection of carbendazim (MBC) in the TCMs is a big challenge for their complex chemical constituents. In this work, a 0D/1D nanohybrid was developed by anchoring 1T-phased MoS 2 quantum dots (QDs) over multiwall carbon nanotubes (MWCNTs) via a facile assembly method. High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis (TGA) together with EIS reveal that the 1T-phased QDs can anchor over MWCNTs via van der Waals forces, and the anchoring improves the nanohybrid surface area and conductivity. Therefore, the electrochemical sensor fabricated based on the MoS 2 QDs@MWCNT nanohybrid shows excellent catalytic activity to MBC oxidation. Under optimized conditions, the sensor presents a linear voltammetry response to MBC concentration from 0.04 to 1.00 μmol•L −1 , a low detection limit of 2.6 × 10 −8 mol• L −1 , as well as high selectivity, good reproducibility, and long-term stability. Moreover, the sensor has been successfully employed to determine MBC in two typical TCMs and the obtained recoveries are in good accordance with the results achieved by HPLC, showing that the constructed sensor plate holds great practical application in MBC analysis with complex matrix.

Preparation of Functionalized Ayous Sawdust‐carbon Nanotubes Composite for the Electrochemical Determination of Carbendazim Pesticide

“…Peak currents and peak potentials were found to vary with pH (Figure 8A). As expected from previous works [44,47,76,79], the peak potentials decreased linearly as the pH increased (R 2 > The obtained slope of À 64 mV/pH suggests an equal number of electrons and protons involved in the electrochemical reaction [44,45,[80][81][82]. At alkaline pH values, the observed low currents resulted from the hydrolysis of Cbz.…”

“…The obtained slope of −64 mV/pH suggests an equal number of electrons and protons involved in the electrochemical reaction [44, 45, 80–82]. At alkaline pH values, the observed low currents resulted from the hydrolysis of Cbz.…”

Multiwalled carbon nanotubes modified two dimensional MXene with high antifouling property for sensitive detection of ochratoxin A

“…Among them, the Ti 3 C 2 -cMWCNTs/GCE shows the largest background currents, and that of the GCE is the least. It is known that the background current is in highly depended on the value of capacity, while the value of capacity is directly proportional to surface area because the dielectric constant ε is almost constant in the same aqueous condition [47,48]. Therefore, the largest background current for Ti 3 C 2 -cMWCNTs/GCE suggests the largest effective surface area, which is consistent with the surface area results.…”

Research on the Comprehensive Evaluation Method for the Automatic Recognition of Raman Spectrum under Multidimensional Constraint

“…It is widely used in various fields such as chemistry, 1 physics, 2 biology, 3 and medicine. 4 With the development of small and miniature Raman spectrometers, in situ detection of samples using Raman spectroscopy technology is the main approach increasingly adopted in field analysis. 5 Raman spectrum detection technology has gradually walked out of laboratories to the market.…”

“…Raman spectrum is regarded as an effective means of substance composition analysis as it reflects the structure of the substance. It is widely used in various fields such as chemistry, physics, biology, and medicine . With the development of small and miniature Raman spectrometers, in situ detection of samples using Raman spectroscopy technology is the main approach increasingly adopted in field analysis .…”