KP X 765
the dried basis.
Description Magnesium Glycerophosphate appears
as white powder.
Magnesium Glycerophosphate is practically insoluble
in ethanol (95).
Magnesium Glycerophosphate dissolves in dilute solu-
tions of acids.
Magnesium Glycerophosphate is hygroscopic.
Identification (1) Mix 1 g of Magnesium Glycero-
phosphate with 1 g of potassium hydrogen sulfate in a
test tube fitted with a glass tube. Heat strongly and
direct the white vapor towards a piece of filter paper
impregnated with a freshly prepared 1 w/v % sodium
pentacyanonitrosylferrate (III) dihydrate solution: the
filter paper develops a blue color in contact with
piperidine.
(2) Ignite 0.1 g of Magnesium Glycerophosphate in
a crucible, add 5 mL of nitric acid to the residue, heat
in a water-bath for 1 min and filter. The filtrate re-
sponds to the Qualitative Tests (2) for phosphate.
(3) Magnesium Glycerophosphate responds to the
Qualitative Tests for magnesium.
Purity (1) Clarity and color of solution
⎯
Dissolve
2.5 of Magnesium Glycerophosphate in 50 mL of water:
this solution is not more opalescent than the reference
suspension
Reference suspension⎯To 30 mL of standard sus-
pension, add 70 mL of water. Prepare when use and
shake well before use.
Standard suspension⎯Prepare as directed in the
reagent under the Test Methods for Plastic Containers.
(2) Acid
⎯
Dissolve 1.0 g of Magnesium Glycero-
phosphate in 100 mL of water and titrate with 0.1
mol/L sodium hydroxide VS (indicator: 2 drops of
phenolphthalein TS): less than 1.5 mL of 0.1 mol/L
sodium hydroxide VS consumed.
(3) Chloride
⎯
Proceed with 0.20 g Magnesium
Glycerophosphate and perform the test. Prepare the
control solution with 0.84 mL of 0.01 mol/L hydro-
chloric acid VS (not more than 0.015 %).
(4) Sulfate
⎯
Proceed with 0.20 g of Magnesium
Glycerophosphate and perform the test. Prepare the
control solution with 0.42 mL of 0.005 mol/L sulfuric
acid VS (not more than 0.1 %).
(5) Phosphate
⎯
Dissolve 2.5 g of Magnesium
Glycerophosphate in 50 mL of water. Pipet 4.0 mL of
this solution and add water to make 100 mL. Pipet 1.0
mL of this solution, add water to make 100 mL and use
this solution as the test solution. To 100 mL of the test
solution, add 4 mL of sulfomolybdic TS and 0.1 mL of
tin (II) chloride TS and allow the mixture to stand for
10 minutes: the color from this solution is not more
intense than that from a solution containing 2 mL of
standard phosphate solution and 98 mL of water (not
more than 0.5 %).
(6) Heavy metals
⎯
Dissolve 1.0 g of Magnesium
Glycerophosphate in 20 mL of water, add 15 mL of
hydrochloric acid and 25 mL of 4-methyl-2-pentanone,
and mix by shaking for 1 minute. After standing, take
the aqueous layer and evaporate to dryness. Dissolve
the residue in 2 mL of dilute acetic acid, add 50 mL of
water and perform the test using this solution as the test
solution. Prepare the control solution with 2.0 mL of
standard lead solution (not more than 20 ppm).
(7) Iron
⎯
Place 67 mg of Magnesium Glycero-
phosphate to a Nessler tube, add water to make 10 mL,
add 2 mL of 20 w/v % citric acid solution and 0.1 mL
of mercaptoacetic acid to mix, make the solution alka-
line by the addition of 10 mol/L ammonia water, add
water to make 20 mL and allow this solution to stand
for 5 minutes: the color from this solution is not more
intense than that from diluted standard iron solution (1
in 10) (not more than 150 ppm).
(8) Glycerol and alcohol-soluble substances
⎯
To
1.0 g of Magnesium Glycerophosphate, add 25 ml of
ethanol (95), mix by shaking for 2 min, filter and wash
the residue with 5 ml of ethanol (95). Combine the
filtrate and the washings, evaporate to dryness in a wa-
ter-bath, dry the residue at 70 °C for 1 h and weigh (not
more than 1.5 %).
Loss on Drying Not more than 12.0 % (1 g, 150 °C,
4 hours).
Assay Weigh accurately 0.2 g of Magnesium
Glycerophosphate, add 40 mL of water to dissolve, add
10 mL of ammonia-ammonium chloride buffer solution,
pH 10 and titrate with 0.1 mol/L disodium
ethylenediaminetetraacetate VS (indicator: 50 mg of
eriochrome black T-sodium chloride TS) until the color
of the solution changes from purple to blue.
Each mL of 0.1 mol/L
disodium ethylenediaminetetraacetate VS
= 2.431 mg of Mg
Containers and Storage Containers—Tight con-
tainers.
Magnesium Hydroxide
Mg(OH)2: 58.32
Magnesium dihydroxide [1309-42-8]
Magnesium Hydroxide, when dried, contains not less
than 95.0 % and not more than 100.5 % of magnesium
hydroxide [Mg(OH)2].
Description Magnesium Hydroxide is a white bulky
powder.
Magnesium Hydroxide is practically insoluble in water
or ethanol (95).
