A novel molecular imprinted probe with hybrid ratio fluorescent for visual detection of imazapyr

Imazapyr (IMA) is a widely used herbicide, and the detection of its residue is of great significance for agricultural cultivation and preventing the potential risk to human health. In this work, a molecularly imprinted probe was prepared by sol–gel method with hybrid ratio fluorescent for specifically visual detection of IMA for the first time, embedding CdTe quantum dots (QDs) (λem = 580 nm) in molecularly imprinted polymers as response signal and Si QDs (λem = 445 nm) in silicon dioxide as internal signal. After binding with IMA, the fluorescence at 580 nm was quenched gradually while the fluorescence intensity at 445 nm remained constant. Under optimal conditions, the fluorescent intensity ratio (I580/I445) shows a good linear relationship with IMA concentration in the range of 5.0–80.0 μM, with a detection limit of 1.4 μM. Additionally, the fluorescent color of the probe solution changes from red to blue under the ultraviolet irradiation of 365 nm, indicating it has the potential for on-site visual detection. And it had been successfully applied to the detection of IMA in Puerariae Lobatae Radix and soil.