Headgroup-Specific Interaction of Biological Lipid Monolayer/Water Interface with Perfluorinated Persistent Organic Pollutant (POP): As Observed with Interface-Selective Vibrational Spectroscopy.

Perfluoro compounds are widely used in various manufacturing processes, which leads to their bioaccumulation and subsequent adverse effects on human health. Using interface-selective vibrational spectroscopy (heterodyne-detected vibrational sum frequency generation (HD-VSFG)), we have elucidated the molecular mechanism of the perturbation of lipid monolayers on the water surface using a prototype perfluorinated persistent organic pollutant, perfluoroheptanoic acid (PFHA). PFHA disrupts the well-ordered all-trans conformation of a cationic lipid (1,2-dipalmitoyl-3-trimethylammonium propane (DPTAP)) monolayer and reduces the interfacial electric field at the lipid/water interface.

On the Behavior of Perfluorinated Persistent Organic Pollutants (POPs) at Environmentally Relevant Aqueous Interfaces: An Interplay of Hydrophobicity and Hydrogen Bonding.

The behavior of perfluorinated persistent organic pollutants (POPs), especially perfluoroalkyl carboxylic and sulfonic acids, at aqueous interfaces is crucial for their transport and speciation in the environment and subsequent immunotoxicity. Here, we investigate the surface prevalence and interfacial interaction of a prototype perfluorinated-POP, perfluoroheptanoic acid (PFHA), with environmentally relevant amphiphiles of varying hydrophobicity and head groups (CH-; : 8 vs 16; -: -OH vs -COOH) using interface-selective vibrational sum frequency generation (VSFG) spectroscopy. SFG intensity spectra in the CH- and OH-stretch regions reveal that PFHA prevails at aqueous interfaces that contain amphiphiles of intermediate chain length such as 1-octanol ( = 8) and heptanoic acid ( = 6).