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

The range of inorganic acid normalities for maximum color formation of the phosphomolybdenum-blue complex (under heating) increases by elevating the ammonium molybdate concentra­ tion, 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 n with either HC104 or H2S04 (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, HC104 and H:S04concentra­ tions, thus avoiding possible errors produced by the use of two separate calibration curves.