Rapid determination of the pesticide ametryn based on a colorimetric aptasensor of gold nanoparticles

A new, simple colorimetric aptasensor based on the aggregation-induced color change of citrate-stabilized AuNPs was designed for the specific and sensitive determination of ametryn. Citrate-stabilized AuNPs with negative surface charges were synthesized via an easy one-pot reaction. Because of the electrostatic interaction between the three-nitrogen hybrid ring of ametryn and gold nanoparticles, the citrate-stabilized AuNPs easily undergo aggregation in the presence of ametryn. Thus, with a color change from wine red to gray, ametryn was visually detected by a colorimetric aptasensor. In addition, the detection result can also be measured quantitatively using a UV-vis spectrophotometer. The aptasensor has good selectivity and sensitivity to ametryn in the linear range of 0–80.0 μg L−1. According to the IUPAC criteria (3σ rule), the detection limit of ametryn is 0.15 μg L−1. Moreover, the aptasensor was successfully applied to the detection of ametryn in Yongding River from Zhaocun, Yizhuang Jingkai Sewage Treatment Plant and Yizhuang Nokia Factory water samples. The recovery reached 98.9–101.6%, 95.7–101.3% and 100.0–103.3%, respectively. The excellent performance of the colorimetric aptasensor in the detection of ametryn indicates its potential applications in the detection of ametryn in more complex environmental samples.