The conservative behaviour of fluorescein

SA Smith, WA Pretorius
2002 Water S.A  
Failure to account for fluorescein absorbance changes with pH may be responsible for some of the apparent non-conservative behaviour of this easily detectable tracer compound. While it is possible to calculate an accurate absorptivity value for fluorescein at every pH, this calculation is not necessary if the sample pH is increased above pH 9 before measuring the absorbance. Intense sunlight degrades fluorescein quickly but even hot samples are stable if kept in the dark.
doi:10.4314/wsa.v28i4.4913 fatcat:5tihzckknnb23pwauwbtoev7eq