Abstract: In this study, amine-functionalized magnetic mesoporous silica@gold nanoparticles-aptamer-complementary DNA-ferrocene complex (NH2-MMS@Au NPs-Apt-cDNA-Fc) was prepared by using aminated magnetic mesoporous SiO2 supported acetamiprid aptamer and ferrocene-labeled complementary DNA (Fc-cDNA) as probes, and used to construct a highly sensitive electrochemical aptasensor with modification-free electrode for rapid detection of acetamiprid. In 0.1 mol/L phosphate buffered saline (PBS) solution (pH 7.4), using a bare glassy carbon electrode as working electrode, the linear range for acetamiprid detection by square wave voltammetry was 0.055 pmol/L–5.5 nmol/L at the optimal incubation time. The limit of detection was 3.2 fmol/L (RSN = 3). Satisfactory results were obtained for the detection of acetamiprid in vegetables. This method effectively avoids the systematic errors caused by the tedious electrode modification and probe fixation processes, is easy to operate, and has high accuracy. It provides a new and simply sensing technology for highly sensitive detection of pesticide residues in foods, and has a good application prospect.

Key words: magnetic mesoporous silica; modification-free electrode; electrochemical aptasensor; rapid detection; acetamiprid