Assessment of a procedure for fractionating organic phosphates in soil and organic materials using gel filtration and h.p.l.c

A method for extracting and fractionating organic phosphates is described. In the fractions, inositol hexaphosphate (IHP) was determined with a carbon detector after high pressure liquid chromatography (h.p.l.c). Sample preparation consisted of a single mild extraction with 0.1M EDTA in 0.3M‐NaOH and a preseparation by gel filtration. Adenosine‐5‐triphosphate (ATP) could also be separated and determined in this way. With a number of samples, clean‐up by gel filtration could not prevent deterioration of the anion exchange column, used in the h.p.l.c. determination. IHP was then determined as total P after isolation by two consecutive gel filtrations. Limits of detection were 5‐50 μg P/g when determining IHP by h.p.l.c. and 0.05‐0.5 μg P/g when determining IHP as total P after isolation by gel filtration. Limits of detection when determining ATP by h.p.l.c. were 5‐50 ng P/g. Results of applying the method to soil and various organic materials are given and discussed.