Colorimetric sensing of atrazine in rice samples using cysteamine functionalized gold nanoparticles after solid phase extraction†
A simple and sensitive colorimetric assay for the determination of atrazine in rice samples using cysteamine–gold nanoparticles (AuNPs) after solid phase extraction has been developed. The approach exploited the benefits of a robust sample pretreatment scheme with a rapid and sensitive colorimetric sensing strategy based on cysteamine–AuNPs. As a result of the hydrogen bonding between atrazine and cysteamine, cysteamine–AuNPs were induced to aggregate with an accompanying distinct color change from wine red to blue. The color change was monitored by UV-vis spectrophotometry or with the naked eye. The difference of the absorbance value at 523 nm was linearly related to the atrazine concentration over the range 0.033 to 6.67 μg g−1, and the limit of detection (S/N = 3) was 0.0165 μg g−1. The spiked rice samples were extracted and purified using Oasis HLB cartridges and satisfactory recoveries (83.23–91.65%) were realized.