IMPROVED SEPARATIONS OF PHYTOPLANKTON PIGMENTS USING TEMPERATURE-CONTROLLED HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Varying the temperature of a polymeric C-18 high performance liquid ch romatography (HPLC) column caused significant changes in elution profi les of carotenoid and chlorophyll (chl) pigment mixtures. High tempera ture operation (60 degrees C) was optimal for carotenoid separations, including the separation of zeaxanthin from lutein. Chlorophyll and ch lorophyll derivative separations were optimal at a column temperature between 10 and 30 degrees C. A protocol is presented that achieves qua ntifiable resolution of all taxonomically important pigments tested by running the analysis at 2 temperatures: 10 and 60 degrees C. Of parti cular significance was the ability to separate divinyl chl a from mono vinyl chl a, chl c(1) from chl c(2), and partial separation of chl c(2 ) and MG 2,4-divinyl phaeoporphorin a(5) monomethyl ester. An example is given of the utility in separating chl c pigments, and lutein and z eaxanthin in natural phytoplankton samples.