Essential trace elements that are required by our body for several actions and immunity and also to prevent some diseases due to the deficiency of the trace elements.
2. Ferrous gluconate
PREPARATION :
Glucose is oxidized by bacterial
fermentation to gluconic acid. The gluconic acid so
obtained is treated with ferrous carbonate to give
ferrous gluconate. It is crystallized with 2 molecules
of water of hydration and dried
(O)
Glucose -------> Gluconic acid
Gluconic acid + Ferrous carbonate + water ------> Ferrous
gluconate
3. Physical and chemical properties :
Color - Yellowish grey or
Pale greenish yellow
Nature - Fine powder or granules
Odour - Burnt sugar like odour
Solubility - Fairly soluble in cold water and
more soluble in warm water
Identification test :
1. A solution of the sample in water gives the
reactions of ferrous salts
2. To a small quantity of the sample add water,
glacial acetic acid and freshly distilled
phenylhydrazine. The mixture is heated on a water
bath for thirty mins. It is then cooled and the inner
surface of the test tube is scratched with glass rod
until crystals of gluconic acid phenylhydrazide
begin to form. After setting aside for 10 mins it is
filtered.
4. The precipitate is dissolved in hot water, mixed with a small amount of
decolourising charcoal and filtered into a test tube. The filtrate is cooled
and the inner surface of the test tube is scratched. White crystals of pure
gluconic acid phenylhydrazide are obtained. They melt at about 202°C
with decomposition.
Standard :
Ferrous gluconate contains NLT 95% and NMT 102% . It is
calculated with reference to the dried substance.
Assay :
An accurately weighed quantity is dissolved in dil. Sulphuric acid
with the aid of gentle heat and titrated with 0.1 N ceric ammonium
nitrate, using Ferroin sulphate as indicator and end point is marked by
the disappearance of the red colour.
This is a redox titration
5. Storage :
Store in a well closed light
resistant container, because it is
affected by light.
Medicinal use :
Category :
Haematinic
It is useful in the prevention
and treatment of iron-deficiency
anemias
6. Ferrous sulphate
FeSO4. 7H₂O
Preparation :
It is prepared by dissolving a slight excess of
iron in dil. sulphuric acid and concentrating to get
green crystals of ferrous sulphate
Fe + H₂SO4 ----> FeSO4 + H₂
Physical and chemical properties :
Color - green or pale bluish-green
Nature - crystalline powder
Odour - odourless
Taste - metallic, astringent taste
Solubility-soluble in water and insoluble in water
7. It effloresces in dry air. When exposed to moist air, it is
slowly oxidised and is coated with a brown basic ferric
sulphate. It combines with alkali sulphates to form double
salts.
Identification test :
Ferrous salt :
1. Solution of a ferrous salt gives with potassium
ferricyanide solution a dark blue precipitate. It is insoluble in
dil. Hydrochloric acid. But it is decomposed by sodium hydroxide
solution.
2. Solution of a ferrous salt gives with potassium
ferrocyanide solution a white precipitate. This rapidly turns
blue and is insoluble in dil. Hydrochloric acid.
Sulphate salt :
Solutions of sulphates gives white precipitate with
barium chloride which is insoluble in hydrochloric acid.
8. Standard :
Contain NLT 98% and NMT equivalent of 105% of ferrous sulphate.
Assay :
1) same method as for ferrous gluconate.
2) An accurately weighed quantity is dissolved in dil. Sulphuric
acid and titrated against 0.1 N potassium permanganate
(self-indicator). Ferrous sulphate is oxidised to ferric sulphate.
Appearance of pale pink color is the end point.
Storage : Since it e�oresces in dry air and is oxidised in
moist air, store in tightly closed containers.
Medicinal use :
Haemanitic. This is the most popular of the ferrous salts
and also the cheapest.
