Colorimetric detection of polycyclic aromatic hydrocarbons using supramolecular cyclodextrin dimer-squaraine constructs

The development of solution-state colorimetric detection methods for highly toxic, environmentally persistent polycyclic aromatic hydrocarbons (PAHs) is reported herein. This method relies on supramolecular chemistry, and in particular on the ability of the PAH analytes to displace a squaraine dye bound with high affinities in beta-cyclodextrin dimer hosts. The displacement of the dye results in visible color changes that are highly specific to each target analyte, resulting in up to 100% successful differentiation among 30 PAH analytes using straightforward image processing procedures and linear discriminant analyses.