A High Efficiency Sers Platform Based on 3d Porous Ppda@Au Nps as Substrate for Detection of Pesticide on Vegetables

Abstract

Nowadays, highly toxic and persistent residues of pesticides in water and food around the world are now a serious problem, and quick and sensitive detection of them is critical to human health. In this work, a 3D composite nanoparticle of porous PDA microspheres and Au NPs (PPDA@Au NPs) was proposed as a SERS substrate to detect pesticides. Porous PDA as substrate was firstly synthesised with F127, dopamine hydrochloride, 1,3,5-TMB under weakly alkaline conditions by a one-step method. Then, HAuCl4 was in-suit reduction on the pore of PPDA spheres and grow sequentially for the reducibility of PPDA. As a result, uniform 3D PPDA@Au NPs with “hot spots” were successfully synthesised as SERS substrates which effectively avoid the agglomeration of the gold nanoparticles to greatly improve the sensitivity and uniformity of the SERS platform. At the same time, methyl parathion, 4-chlorophenol and 2, 4-D as representatives of pesticides were detected with the proposed PPDA@Au NPs based SERS platform, the detection limit was lower to 7.26 ng/mL, 7.52 ng/mL and 11 ng/mL, separately. And the current work develops a simple preparation method to prepare sensitive and uniform SERS platform PPDA@Au NPs which can be hopefully applied in the actual pesticide and drug testing.

Keywords: Porous Particles, PPDA@Au NPs, SERS platform, Pesticide