A colorimetric sensor based on citrate-stabilized AuNPs for rapid pesticide residue detection of terbuthylazine and dimethoate

A new colorimetric sensor based on citrate-stabilized AuNPs was proposed for the rapid pesticide residue detection of both terbuthylazine (TBA) and dimethoate (DMT) with ultra-sensitivities and high selectivities. The detection mechanisms have been verified via FT-IR, UV–vis spectra, Zeta Potential, TEM and DLS. Under the optimized experimental conditions, 30 kinds of potential environmental pollutants have no interference on the TBA or DMT detection indicating the high selectivities of our AuNP-based colorimetric sensor. The limit of detections (LODs) of TBA and DMT by eye vision are respectively 0.3   μM and 20   nM, and those based on calculation (3σ/S) are 0.02   μM and 6.2   nM, respectively. The minimum detectable concentrations of TBA or DMT are much lower than the maximum residue limit (MRL) regulated by the governments of EU and China. The linear relationships of the UV–vis spectrometry demonstrate that our AuNP-based colorimetric sensor can be used for the quantitative analysis of TBA in the range of 0.1–0.9   μM, and DMT in the range of 1–40   nM. Finally, our AuNP-based colorimetric sensor is also verified to have a good practical applicability for TBA or DMT detection in the real environmental samples.