placed in a boiling water both for 50mins after which the
precipitated ferric phytate was collected by centrifugation
washed thoroughly with 30cm3
of trichloroacetic acid and
50cm3
of water. 3.0cm3
of 1.5M NaOH in added to the
precipitate obtained and diluted with 30cm3
distilled water is
obtained the resulting ferric hydroxide is coagulated by
heating. Ferric hydroxide was centrifuge washed with
distilled water and dissolve with 40cm3
of 3.2M nitric acid
and made up to 100cm3
distilled water. The iron content
was determined by an atomic absorption
spectrophotometer. From the iron content, the phytate
content was calculated assuming a constant 4:6 (iron,
phosphorous) molecular ratio in the precipitate. Amount of
phytate in sample is calculated as
Atomic weight of iron =55.85g
Atomic weight of phosphorous =31g
Molecular weight of phytate acid (C6 P6 O24 H18 ) =660.8g
Iron in sample =X micrograms from standard curve
converting micrograms to micromoles.
= x/55.85= Y micromoles of Fe.
Using molecular ratio of Iron phosphorous 4:6 phosphorous
(p) = 6/4 x y = molecules P = Z
Thus PA= 660.8/185.82 x Z
N.B: 185.82 is x molecular weight of P.