Electrochemical determination of trace pesticide residues based on multiwalled carbon nanotube grafted acryloyloxy ferrocene carboxylates with different spacers

Abstract

Food safety has always been a topic that attracts attention. The residues of pesticides will directly or potentially affect and threaten human health when they are used to protect crops. Therefore, it is important to rapidly, promptly and accurately monitor pesticide residues in food. In this study, a novel nanohybrid composite with good electrochemical responses was developed, and it was prepared by the esterification reaction of hydroxyl-terminated polybutadiene (HTPB) with MWCNTs-COOH, followed by atom transfer radical polymerization of 4-acryloyloxybutyl(ethyl) ferrocene carboxylates with different spacers. The nanohybrid composites were characterized by FTIR, TGA, Raman, XRD, XPS, SEM and TEM techniques. Cyclic voltammetry (CV) determination showed that a longer spacer between the side ferrocene groups and main chains endowed the electrochemical modified electrodes with active electroresponse, obvious redox current and reversible electrochemical properties because of the faster electron transfer rates. The modified electrode sensor with a longer spacer was used to detect melamine and trichlorfon residues by CV and differential pulse voltammetry (DPV) techniques. The sensor had a good linear relationship over a wide concentration range, a maximal recovery of ca. 112.4% and a low detection limit of about 1.5 × 10⁻⁷ and 3.5 × 10⁻⁸ mol L⁻¹, respectively.