The new HORIBA Duetta fluorescence and absorbance spectrometer offers many unique benefits for molecular spectroscopy. It is primarily thought of as a spectrofluorometer that combines absorbance and fluorescence spectroscopy to correct the fluorescence fingerprint for concentration-related effects. To learn more about this unique inner-filter Effect (IFE) correction, refer to our Duetta Applications Note entitled: “Automatic Correction of Fluorescence Spectra for Primary and Secondary Inner-filter Effects (IFE) with DuettaTM ”. However, it is important to note that Duetta can also be used as a precise absorbance spectrometer. This application note explores the use of Duetta for a common absorbance application, the Protein A280 application.