Vesicular coacervative extraction of bisphenols and their diglycidyl ethers from sewage and river water

Abstract

Coacervates made up of vesicles of decanoic acid, induced by tetrabutylammonium, are proposed for the extraction of bisphenols A and F (BPA, BPF) and their corresponding diglycidyl ethers (BADGE and BFDGE) from sewage and river water. The driving forces for the extraction were hydrophobic, hydrogen bonding and π-cation. Actual concentration factors depended mainly on the amount of decanoic acid and tetrabutylammonium making up the coacervate. Under optimal experimental conditions, they were 569, 561, 500 and 477 for BPA, BPF, BADGE and BFGDE, respectively. Extractions were independent of the presence of salts up to 1 M and the temperature up to 60 °C. Equilibrium conditions were reached in 5 min. The combination of vesicular coacervation with liquid chromatography and fluorescence detection at λ exc 278 nm and λ em 306 nm permitted the quantification of the target pollutants with detection limits of 9–10 ng/L. The method was applied to their determination in raw and treated sewage and river samples. No clean-up steps were necessary. Apparent recoveries of bisphenols and their diglycidyl ethers in the environmental water samples ranged from 95 to 102%. The concentrations of BPA and BPF in samples were between 0.1 and 1.7 μg/L. BADGE was found mainly in wastewater influents, at concentrations ranging between 0.49 and 1.15 μg/L, whereas BFDGE was only found in one of the 11 samples analysed.