A Novel Conjugated Fluorescent Probe and its Application to Nitenpyram Detection

In this study, a fluorenyl pyridine-based (FPD) conjugated polymer was synthesized and used as a fluorescent probe to efficiently and rapidly detect nitenpyram (NIT). NIT can quench the fluorescence of FPD, and the quenching efficiency can reach up to 82.75%. The linear ranges of NIT detection in ethanol–phosphate buffered saline and ethanol were 0–64 μM and 0–45 μM, respectively, and the detection limit was as low as 0.62 μM. FPD has good selective recognition and anti-interference abilities for NIT. Combined with a study on the fluorescence spectral anisotropy of FPD and NIT, the mechanism of the reaction between FPD and NIT was explored. It was concluded that FPD and NIT quenched their fluorescence under the combined action of π–π stacking and hydrogen bonding. Finally, NIT was recovered in organic cabbage, and the recovery rates were between 91.60% and 110.21%. The relative standard deviation was within 3.84%, indicating that FPD had high accuracy and good repeatability for the quantitative detection of NIT, further proving the feasibility of the fluorescence sensing method in practical applications.