Ratiometric electrochemical sensor for sensitive detection of sunset yellow based on three-dimensional polyethyleneimine functionalized reduced graphene oxide aerogels@Au nanoparticles/SH-β-cyclodextrin.

Electrochemical methods have been deemed effective strategies for the detection of dye additive sunset yellow (SY) owing to their low cost, good stability, and high sensitivity. However, the application of the existing sensors with single electrical signal response is limited by their inadequate sensitivity and large background interference. Herein, a ratiometric electrochemical strategy with a dual signal was developed to detect SY. The strategy had an intrinsic built-in correction to the effects from the system, and thus reduced the influence of environmental change. 3D polyethyleneimine functionalized reduced graphene oxide aerogels@Au nanoparticles/SH-β-cyclodextrin (PEI-rGAs@AuNPs/SH-β-CD) was used as the sensing material due to its 3D macroporous microstructure with high specific surface area and excellent electronic conductivity. Guest molecule methylene blue (MB) was chosen as a probe molecule, which formed an inclusion host-guest complex with a SH-β-CD host in advance. The target molecule SY displaced MB from the CD cavities, resulting in the decrease of MB current and the increase of SY current. With the logarithmic value of I/I as the readout signal, the detection limit of the developed ratiometric electrochemical sensor reached as low as 0.3 nM, confirming the excellent sensitivity. Furthermore, this strategy exhibited good selectivity and repeatability, and could be used for the detection of SY in a real sample.