Pendant-drop method coupled to ultraviolet-visible spectroscopy: A useful tool to investigate interfacial phenomena.

•A new approach to simultaneously investigate surface tension and UV–vis spectra was developed.•The axisymmetric drop shape analysis coupled to diffuse reflectance spectroscopy was used.•The analysis requires low sample volumes and small analyte concentrations.•The disaggregation of an organic dye driven by surfactants molecules was followed.•The activity of an enzyme in the presence of phospholipid monolayers was investigated.