Abstract
In this work, a covalent-organic framework with high carbon and nitrogen content microstructures (named COF-LZU1), assisted by 3D nitrogen-containing kenaf stem composites (represented as COF-LZU1/3D-KSCs), was constructed. Moreover, it was utilized for immobilizing acetylcholinesterase (AChE) for identifying trichlorfon, a commonly applied organophosphorus (OP) pesticide. The development of COF-LZU1/3D-KSC was affirmed by SEM, PXRD, and EDXS. The findings confirmed that COF-LZU1 microstructures were uniformly developed on 3D-KSC holes using a one-step synthesis approach, which can substantially enhance the effective surface area. Also, the COF-LZU1/3D-KSC composite contains not only the nitrogen element in COF-LZU1 but also the nitrogen element in 3D-KSC, which will greatly improve the biocompatibility of the material. The AChE/COF-LZU1/3D-KSC integrated electrode was fabricated by directly fixing a large amount of AChE on the composite. At the same time, the integrated electrode had good detection efficiency for trichlorfon. Improved stabilization, a wide-linear-range (0.2–19 ng/mL), and a lower detection limit (0.067 ng/mL) have been displayed by the sensor. Therefore, this sensor can be used as an important platform for the on-site detection of OP residue.
Highlights
Organophosphorus pesticides (OPs), such as Trichlorfon, have been thoroughly used in agriculture due to their powerful insecticidal ability (Ma et al, 2018)
The COF-LZU1s may spread over the pores of 3D-KSC, and had good biocompatibility because they contain no metal elements and only carbon, nitrogen, and oxygen elements
The anodic peak currents of AChE/3D-KSCE and AChE/GCE decreased irregularly. This may be due to the decrease of enzyme modification, resulting in the narrowing of the detection range (Figure 2B) and could be related to the fact that the glassy surface of the carbon electrode is smooth and the AChE can not be immobilized for a long time (Figure 2C)
Summary
Organophosphorus pesticides (OPs), such as Trichlorfon, have been thoroughly used in agriculture due to their powerful insecticidal ability (Ma et al, 2018). The COF-LZU1s may spread over the pores of 3D-KSC, and had good biocompatibility because they contain no metal elements and only carbon, nitrogen, and oxygen elements. The developed trichlorfon sensor based upon the AChE/COF-LZU1/3D-KSC composites showed a wide-range linearity, lower detection limitations, and good stability. The AChE/COF-LZU1/3D-KSC electrode was fabricated by dropping a 5 μL AChE solution with various concentrations upon the electrode surface, followed by dessication. The first (DPV) signal was (IP,control) recorded in 0.1 M PBS of pH 7 alongwith 1 mM ATCl. After that, the electrode was cleaned with distilled water, placed inside an aqueous solution having a preferred concentration of trichlorfon for about 10 min. The inhibition rate of trichlorfon was estimated as below: Inhibition (%)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call