Preparation and comparison of molecularly imprinted polymer fluorimetric nanoprobe based on polymer dots and carbon...

In this study molecularly imprinted polymers (MIP) based on carbon quantum dots (CQDs) and polymer dots (PDs) are developed for selective determination of acetamiprid using fluorometry. The measurement is based on the fluorescence quenching of CQDs and PDs in the presence of acetamiprid. PDs were prepared using a one-step aqueous synthesis method from ascorbic acid and diethylenetriamine at room temperature. CQDs were prepared from the same materials using the hydrothermal method at 180 °C. These particles were characterized using field emission scanning electron microscopy (FE-SEM), FTIR, dynamic light scattering (DLS), X-ray diffraction (XRD), UV-Vis, and fluorescence. The quantum yield was 47% for PDs and 8% for CQDs. Then, molecularly imprinted polymers (MIP) were prepared based on PDs and CQDs using reverse microemulsion method. The fluorescence quenching of CQD@MIPs and PD@MIPs was investigated at an excitation wavelength of 350 nm and emission wavelength of 440 nm in the presence of a template. Other variables affecting the fluorescence peaking were optimized using design expert software. The results illustrate that the use of PD@MIPs had a wide dynamic range 0.08-109 nmol L^-1, good accuracy and detection limit of 0.02 nmol L^-1, while using CQD@MIPs led to a lower dynamic range 0.36-64 nmol L^-1, and detection limit of only 0.11 nmol L^-1. The responses of the optical nanoprobe for acetamiprid in water (recovery 92-102%) and apple (recovery 92-103%) were also investigated. Graphical abstract Schematic representation of preparation polymer dots (PDs), carbon quantum dots (CQDs), PDs coated with imprinted polymers (PD@MIPs), and CQDs coated with imprinted polymers (CQD@MIPs) in the presence and absence of acetamiprid.