Optimization of Conditions for Accurate Phosphonate and Total Phosphorus Assay on Lipid Samples, in Conjunction with Thin-Layer Chromatography

Abstract

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum- blue complex (under heating) increases by elevating the ammonium molybdate concentration, and at a ratio of molybdate molarity/acid normality equal to 10, there is maximum color development at any acid normality in the range 1-4 ɴ with either HClO4 or H2SO4 (or their mixtures). On the basis of these features a revised method is described for the accurate determination of phosphonate-P percent of total-P. on lipid extracts and on TLC bands. The color at the final step, in both cases, is developed under the same conditions of molybdate, HClO4 and H2SO4 concentrations, thus avoiding possible errors produced by the use of two separate calibration curves.