Molecularly Imprinted Silica Nanospheres Embedded CdSe Quantum Dots for Highly Selective and Sensitive Optosensing of Pyrethroids

Abstract

This paper reports the molecularly imprinted polymer (MIP)-based fluorescence nanosensor which is developed by anchoring the MIP layer on the surface of silica nanospheres embedded CdSe quantum dots (QDs) via a surface molecular imprinting process. The molecularly imprinted silica nanospheres (CdSe@SiO2@MIP) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), IR spectroscopy, and so forth, which demonstrated the formation of uniform core−shell lambda-cyhalothrin(LC)-imprinted silica nanospheres. The synthesized CdSe@SiO2@MIP shows higher photostability, and allows a highly selective and sensitive determination of LC via FL intensity decreasing when removal of the original templates. The CdSe@SiO2@MIP was applied to detect trace LC in water without the interference of other pyrethroids and ions. Under optimal conditions, the relative FL intensity of CdSe@SiO2@MIP decreased linearly with the increasing LC in the concentration in the range of 0.1−1000 μM with a detection limit (3σ) of 3.6 μg·L−1. It is found that LC can quench the luminescence of CdSe@SiO2@MIP in a concentration-dependent manner that is best described by a Stern−Volmer-type equation. The possible mechanism is discussed.