An aptamer-based colorimetric sensing of acetamiprid in environmental samples: Convenience, sensitivity and practicability

Convenient and practical detection of the ultra-low concentration of single-component pesticide residue in real environmental samples is crucial for the assessment of environmental risks caused by this pesticide. Herein, a simple and rapid colorimetric sensor for the detection of acetamiprid in real environmental samples and agricultural products was constructed by the direct and sensitive response of positively charged gold nanoparticles ((+) AuNPs) to the aptamer structure change induced by acetamiprid. (+) AuNPs’ response to target is direct and sensitive with no need of the salt-induced process. The affinity interaction between aptamer and target is carried out in an isolated and optimized system without interference. Consequently, this colorimetric sensor has high sensitivity. Even with the naked eye, acetamiprid as low as 7.5 × 10−8 M was observed to cause the color change of (+) AuNPs within minutes. The detection limit of the colorimetric sensor was calculated to be 5.6 × 10-10 M, which was about one order of magnitude lower than that in (-) AuNPs system and far lower than that of other colorimetric methods. Moreover, it was found that the high specificity of aptamer recognition could withstand the complexity of real samples. Compared with the standard HPLC method, the detection results of the colorimetric analysis have excellent accuracy and reliability. In particular, the processing of the real sample in the colorimetric sensor is much simpler and does not require professional chromatographic separation.