Development of WaveFlex Biosensor for Rapid Detection of Glyphosate Herbicide in Real Agricultural Products

Glyphosate is widely used in agriculture and forestry as herbicide. However, excessive use may lead to water pollution and food safety hazards, which are extremely harmful to organisms. In view of this, a WaveFlex biosensor based on localized surface plasmon resonance (LSPR) effect was fabricated for rapid and accurate detection of glyphosate. The distribution of the evanescent field in the fiber is simulated using the RSoft software. The simulation shows that the structure can excite more evanescent waves (EWs). In order to stimulate the LSPR effect, gold nanoparticles (AuNPs) are fixed on the surface of the fiber. Zinc oxide nanowires (ZnO-NWs) and molybdenum disulfide nanosheets (MoS2-NSs) were sequentially immobilized on the surface of the fiber to increase the reaction area of the sensor. Reproducibility test, reusability test, pH test, stability test, and selectivity test were carried out to evaluate the sensing performance. The results showed that the sensor had good sensing performance. Finally, it was tested in real samples (soybean and corn), and the relative standard deviation (RSD) was small, indicating that it could be applied in the actual environment. The linear detection range of the sensor is 0–
$80~\mu \text{M}$
, limit of detection (LoD) is
$3.53~\mu \text{M}$
, the sensitivity is 76.4 pm/
$\mu \text{M}$
, and the limit of quantitation (LoQ) is
$11.65~\mu \text{M}$
.