A spectrofluorometer to measure difference in fluorescence spectra: a simple method for improving sensitivity

To accurately measure small changes in fluorescence spectra a difference spectrofluorometer was designed and constructed. The instrument simultaneously measures fluorescence from two samples. Routinely, two identical samples are used; one serving as the reference while the other is subjected to experimentation. This procedure minimizes variations in fluorescence arising from instabilities in either the sensitivity of the instrument or from the sample with time.