Identification of 15 Phthalate Esters in Commercial Cheese Powder via Cyclodextrin-Promoted Fluorescence Detection

A challenge for detecting phthalates in commercial products such as cheese powders is that the composition of the products is highly complex, and current methods for detection rely on gas chromatography-mass spectrometry, which is not portable and cannot be used by individual consumers at a time and place of their choosing. Herein, we report the development of a new method for phthalate detection in cheese powder using cyclodextrin-promoted fluorescence detection, in which the presence of the phthalate analytes leads to highly analyte-specific changes in the fluorescence emission signal of a fluorophore bound in a cyclodextrin cavity. This method relies on subtle changes in the analyte affinity for the fluorophore and the cyclodextrin cavity and provides for markedly more straightforward sample preparation procedures and an extremely rapid read-out signal, with potential for the development of portable fluorescence sensors. Using this method, we were able to detect 15 phthalate esters with highly analyte-specific responses and at concentrations as low as 0.12 μM, which is well below regulatory levels of concern. Computational investigations strongly support the observed experimental trends.