A novel self-enhanced electrochemiluminescent aptamer sensor based on ternary nanocomposite PEI/RuSi-MWCNTs for the detection of profenofos residues in vegetables.

In this work, a novel ternary nanocomposite of PEI/RuSi-MWCNTs was designed and synthesized for the first time, which an ultrasensitive and self-enhanced electrochemiluminescent (ECL) aptasensor was developed for the detection of profenofos residues in vegetables. The self-enhanced complex PEI-Ru (II) enhanced the emission and stability of ECL, and the multi-walled carbon nanotubes (MWCNTs) acted as an excellent carrier and signal amplification. The PEI/RuSi-MWCNTs were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS). The incorporation of gold nanoparticles (AuNPs) improved the performance of the sensor and provided a platform for the immobilization of the aptamer. The results of the experiment showed that the presence of profenofos significantly suppressed the electrochemiluminescence intensity of the sensor. The detection sensitivity of the aptamer sensor was in the range of 1 × 10 to 1 × 10 ng/mL. Under optimal conditions, the limit of detection (LOD) of the sensor for profenofos was 1.482 × 10 ng/mL. The sensor had excellent stability, reproducibility and specificity. The recoveries of the sensor ranged from 92.29 % to 106.47 % in real sample tests.