DETERMINATION OF PHOSPHORUS IN DAIRY-PRODUCTS BY SAMPLE WET DIGESTIONIN A MICROWAVE-OVEN

A procedure has been developed for rapid mineralization of milk and da iry product samples with different reagents in closed vessels in a mic rowave oven, which is compatible with a final spectrophotometric deter mination of phosphorus that is performed following standardized proced ures. Perchloric acid along with hydrogen peroxide gave the best diges tion performance without interference in the subsequent spectrophotome tric measurement. The sample exposure time in the microwave oven was 1 5 min. The results for the various product assays were compared with t he results of incineration of identical samples in a crucible furnace. The two procedures gave similar levels of precision, with coefficient s of variation of around 2%. Accuracy was evaluated using certified mi lk samples and the values obtained were within the confidence interval s for these products.