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 mu g g(-1), and the limit of detection (S/N _ 3) was 0.0165 mu g g(-1). The spiked rice samples were extracted and purified using Oasis HLB cartridges and satisfactory recoveries (83.23-91.65%) were realized.