Colorimetric detection of pyrethroid metabolite by using surface molecularly imprinted polymer

Abstract

A simple colorimetric method was developed for the detection of 3-Phenoxybenzaldehyde (3-PBD), the metabolite of pyrethroid pesticides, based on surface molecularly imprinted polymer (MIP). In this method, MIP layer was coated on the surface of monodispersed silica nanoparticles via sol-gel process with 3-Aminopropyltriethoxysilane (APTES) and phenyltrimethoxysilane (PTES) as monomers. Compare with single functional monomer, APTES and PTES can interact with 3-PBD mainly by hydrogen bonding and π-π staking interaction, which makes the synthetic MIPs show better affinity and absorption capacity towards target than that of signal functional monomer. After eluted from MIP nanoparticles, the 3- PBD resulted in a distinctive color fading by potassium permanganate reduction. Taking advantage of this phenomenon, the 3- PBD could be detected by recording the absorption of potassium permanganate solution with MIPs as the recognition element. The MIPs, synthesized under various conditions, were characterized by fourier transform infrared spectrometry and scanning electro microscopy. Meanwhile, their absorption performance were also investigated. Under the optimum condition, the proposed method exhibited a linear concentration range of 3-PBD from 0.1μgmL−1 to 1μgmL−1 with a lower detection limit of 0.052μgmL−1 (S/N=3). Moreover, this method was further used to detect 3-PBD in real samples form river water, fruit juice, and beverage. Satisfactory recovery was achieved in the range of 90.0∼98.9%, which clearly demonstrating the potential value of this strategy in the detection of total pyrethroid pesticides.