UV–vis, FT-IR, fluorescence and synchronous fluorescence spectra are applied to discuss the inherent binding information of model protein bovine serum albumin (BSA) with perfluorinated surfactant trimethyl-1-propanaminium iodide (FC-134). According to the results analyzed from Stern–Volmer equation, FC-134 can quench the fluorescence intensity of BSA via a dynamic quenching mechanism with complex formation. The thermodynamic parameters are calculated, revealing that hydrophobic force is the main interaction driven force. The binding constants and number of binding sites are also obtained. With the aid of site markers—warfarin and ibuprofen, we first report that FC-134 primarily binds to tryptophan residue Trp-214 of BSA within site I (sub-domain IIA).Graphical abstractHighlights► FC-134 binds to tryptophan residue Trp-214 of BSA within site I (sub-domain IIA). ► FC-134 can quench BSA via a dynamic quenching mechanism with complex formation. ► The interaction with bovine serum albumin is found to be very strong. ► The study is expected to open us new applications of fluoro-surfactant.

The microphase adsorption-spectral correction (MPASC) technique was described and applied to the study of the interactions of fluorinated surfactants such as potassium perfluorooctanesulfonate (PFOS) and potassium perfluorobutanesulfonate (PFBS) with human serum albumin (HSA). Sodium octanesulfonate (SOS) was also studied as non-fluorinated surfactant. The aggregation of PFOS, PFBS and SOS obeys the Langmuir monolayer adsorption. The results show that the adsorption ratios of surfactants to HSA are PFOS:HSA = 120:1, PFBS:HSA = 205:1 and SOS:HSA = 18:1. The adsorption constants are KPFOS–HSA = 5.01 × 103, KPFBS–HSA = 9.79 × 102 and KSOS–HSA = 4.03 × 103. The detection limits are 2.7 mg/L for BSA using PFOS, 3.1 mg/L using PFBS and 3.1 mg/L using SOS. It was found that fluorinated surfactant exhibited stronger interaction with protein than hydrogenated one, and fluorinated surfactant with long hydrophobic chain exhibited stronger interaction with protein than that with short hydrophobic chain.