Recent developments in porphyrin separations using capillary electrophoresis with native fluorescence detection

A mixed anionic surfactant buffer system is used in the micellar electrokinetic chromatography (MEKC) separation of porphyrin carboxylic acids as well as hematoporphyrin derivatives (HPD) at physiological pH with untreated capillaries. The resolution of type I II, III and IV isomers of coproporphyrin is achieved in bile salt micellar solution. The effects of altering the composition of sodium taurodexyocholate (TDC) and triton QS-15 (QS) on the separation efficiency of the porphyrins are presented. The results show that separation efficiencies are enhanced by using the mixture of bile salt and triton micelles. The limits of detection (LOD) for the porphyrin acids are significantly improved with laser-induced fluorescence (LIF) detection of the native porphyrin fluorescence to the 1 - 10 nM range.