posted on 2021-09-08, 11:36authored byHengyan Ma, Mengya Li, Ting Yu, Hui Zhang, Minghua Xiong, Feng Li
In the present study, a magnetic
mimic multi-enzyme system was
developed by encapsulating the aryloxyphenoxypropionate (AOPP) herbicide
hydrolase QpeH and alcohol oxidase (AOx) in zeolitic imidazolate framework
(ZIF-8) nanocrystals with magnetic Fe3O4 nanoparticles
(MNPs) to detect AOPP herbicides. The structural, protein loading
capacity and loading ratio, porosity, and magnetic properties of QpeH/AOx@mZIF-8
were characterized by scanning electron microscopy, X-ray diffraction,
Fourier transform infrared spectroscopy, thermogravimetric analysis,
nitrogen sorption, and vibrating sample magnetometry. An AOPP herbicide
colorimetric biosensor made with QpeH/AOx@mZIF-8 had the highest sensitivity
toward quizalofop-P-ethyl (QpE) with a limit of detection of 8.2 μM.
This system was suitable to detect two other AOPP herbicides, including
fenoxaprop-P-ethyl (FpE) and haloxyfop-P-methyl (HpE). The practical
application of the biosensor was verified through quantitative analysis
of QpE residues in industrial wastewater and field soils. Furthermore,
QpeH/AOx@mZIF-8 exhibited excellent long-term storage stability (at
least 50 days), easy separation by magnet, and reusability (at least
10 cycles), supporting its promising role in simple and low-cost detection
of AOPP herbicides in real environmental samples.