MEASUREMENT OF AMORPHOUS FERRIC PHOSPHATE AS AN ASSESSMENT OF IRON BIOAVAILABILITY

A method for measuring amorphous ferric phosphate in complex salt mixt ures and animal diets is described. The procedure uses citrate solutio ns for extraction of salt mixtures and tartrate solution for extractio n of prepared diets. Tron in the solution is then determined colorimet rically. Crystalline ferric phosphate, which has no iron bioavailabili ty, is not extracted by either solution. Thus, the procedure can deter mine if the amorphous form, which has a high iron bioavailability, is present. The procedure was tested on gypsy moth artificial diet and We sson salt mixture, which is a salt supplement of the diet.