β-Cyclodextrin-Stabilized Au Nanoparticles for the Detection of Butyl Benzyl Phthalate

Currently, developing new types of simple and effective detection methods of phthalate plasticizers (PAEs) remains challenging, whereas the detection process of the traditional instruments is tedious and laborious. With regard to PAEs, their intrinsically poor Raman activity and very low affinity onto metallic surfaces seriously obstruct the realization of directly effective surface-enhanced Raman spectroscopy (SERS) detection. Here, a dual-mode sensing system with the effective and specific detection of trace butyl benzyl phthalate (BBP, one of PAEs) was demonstrated by constructing β-cyclodextrin (β-CD) stabilized AuNPs (AuNPs@β-CD) colloid. The AuNPs@β-CD assemblies could achieve the enrichment of trace BBP by the hydrophobic cavities of β-CD units, which significantly improved the detection sensitivity. Serving as macromolecular binder and switchable Raman reporters, BBP could assemble AuNPs@β-CD into photonic clusters with different shapes. The obtained BBP-triggered AuNPs@β-CD clusters are able to amplify the corresponding SERS signals due to the abundant hot spots with a lowest detection limit of 0.01 μM. In the colorimetric analysis of detecting BBP, the colorimetric distinguishable response can be accurately quantified via UV–vis spectroscopy with AuNPs@β-CD clusters acting as naked-eye indicators and a detection limit as low as 14.9 nM. Particularly, the proposed colorimetric/SERS sensor was applied to evaluate BBP in liquor and rice wine and the recovery of BBP added to liquor and rice wine samples was 90–108% for UV–vis spectroscopy and 87–109% for SERS assay. The corresponding vibrational bands in supramolecular complexes composed of BBP and β-CD was recognized by the density functional theoretical simulation. Our proposed indirect detection strategy of BBP opens a new avenue to design novel and effective solvatochromic and/SERS-based sensing systems in the field of trial applications.