Highly selective recognition of acrylamide in food samples using colorimetric sensor based on electrochemically synthesized colloidal silver nanoparticles: Role of supporting agent on cross-linking aggregation

Abstract

Acrylamide (AA) which occurs during carbohydrate-rich foods processed at high temperatures has been known as a neurotoxic, genotoxic, and probable carcinogenic compound to humans. In this study, thiourea (TU) is used as a supporting agent for the direct recognition of AA based on the cross-linking aggregation of electrochemically synthesized colloidal silver nanoparticles (e-AgNPs). The effect of TU on the AA recognisability was investigated using UV–vis absorption spectra, TEM, DLS, FTIR, and Raman analysis. The obtained results show that the partial substitution of the citrate layer on the surface of e-AgNPs by TU plays an important role in the AA recognisability of colorimetric sensors. At the concentration of 1 μΜ, TU can replace the citrate layer capped on the surface of e-AgNPs leading to the large changes in the dispersion state of e-AgNPs in acid conditions. This replacement helped AA easily adsorb and interact with the e-AgNPs via the amine group, resulting in a change in color and absorbance of the e-AgNPs-TU solution. This new design selectively responds to AA but does not show a color change with other agents. Under optimized conditions, the analysis of the dispersion state variation of e-AgNPs showed excellent sensing performance toward AA with a good linear in the range of 0.1–1000 μΜ (R2 = 0.99) and a limit of detection (LOD) of 0.024 μΜ. Our study also reveals that the e-AgNPs-TU-based colorimetric sensor can be effectively utilized for the determination of AA in the real biscuit and snack samples with an RSD value of 4.1%.