A theoretical method for the high-sensitivity fluorescence detection of PAEs through double-substitution modification.

A highly sensitive method for the detection of phthalate acid ester (PAE) derivatives by fluorescence spectroscopy based on a double-substitution modification is reported. The fluorescence intensities of 18 PAE derivatives and the template PAEs after docking with the protein bovine serum albumin (BSA) are compared; the fluorescence intensities of the PAE derivatives increase significantly (28.20 to 110.00 times) with high sensitivities, but the functionalities (stability and insulation) are not affected. The persistence, mobility, and toxicity of the PAE derivatives are reduced by varying degrees, and their amounts of bioaccumulation are not significantly changed, indicating that the derivatives are more environmentally friendly. Within the wavelength range 240-420 nm in the fluorescence spectrum, there is no interference between the PAE derivatives and polycyclic aromatic hydrocarbons (PAHs), and the derivatives can be detected with good precision. Based on the analysis of fluorescence characteristics using a 2D quantitative structure-activity relationship (QSAR) model, the occupied orbital energies and Mulliken charge numbers are the main factors that influence the spectral characteristics of the PAE derivatives.