Synchronous fluorescence spectrometry: Conformational investigation or inner filter effect?

Synchronous fluorescence spectrometry has become a common tool to investigate conformational changes in proteins due to the presence of other molecules (quenchers). The same pattern is always followed, leaving aside the possibility of interfering effects that make conclusions incorrect. In this paper, we discuss the main cause of a wrong understanding of synchronous fluorescence spectrometry in a large number of papers published in many different journals. Based on the principles of synchronous fluorescence spectrometry, we perform a simple correction method of synchronous spectra taking into account inner filter effects. This criticism tries to demonstrate that the interpretation of synchronous fluorescence spectrometry is not as easy as it seems.