INTERFERENCE OF INCOMBUSTIBLE PHYTATES IN ANALYSIS OF PLANT PHOSPHOLIPIDS ON LATROSCAN CHROMARODS

The thin layer chromatographic separation of lipids on Chromarods, followed by measurement of organic carbon in the latroscan TH-10 Mark II Analyser, normally leaves the Chromarods ready for immediate reuse. However, a polar lipid fraction derived from rapeseeds included a component that resisted complete combustion on the Chromarod-S (silicic acid), although sterols, triglycerides, and phospholipids left no detectable residue. The component was mobile in organic/water solvent systems containing acids and contained magnesium and zinc. By comparison with authentic standards it was shown to be phytin, a salt of phytic acid, which is found in several commercially important oilseeds. The incomplete combustion is attributed to formation of oxides or carbonates of magnesium, calcium, or zinc. © 1979, Oxford University Press. All rights reserved.