Packaging and storage—
Preserve in well-closed containers. Store at 25
, excursions permitted between 15
and 30
.
Completeness of solution—
Dissolve 10 g in 20 mL of boiling water in a 200-mL volumetric flask, add 150 mL of water, allow to cool, dilute with water to volume, and mix: the solution is clear.
Microbial limits 
61
—
It meets the requirements of the tests for absence of
Salmonella species and
Escherichia coli and for absence of
Staphylococcus aureus and
Pseudomonas aeruginosa; the total aerobic microbial count is less than 1000 per g.
Loss on drying 731:
not more than 10.0% after it has been dried at 105
for 2 hours, 2 g of the finely ground powder being used for the test.
Residue on ignition 281—
Multiply the percentage of
Calcium found by 3.4. The residue on ignition does not exceed this percentage by more than 0.05%.
pH, Chloride, Iron, and Reducing sugars—
Dissolve 10.0 g in 20 mL of boiling water in a 100-mL volumetric flask, allow to cool, dilute with water to volume, and mix. Use the solution for the following tests.
pH 791—
The pH of the solution is between 4.5 and 7.0.
Chloride 221—
A 10-mL portion of the solution shows no more chloride than corresponds to 0.20 mL of 0.020 N hydrochloric acid (0.014%).
Iron—
To 10 mL of the solution add 0.5 mL of hydrochloric acid and 3 drops of
potassium ferrocyanide TS: the solution does not become blue within 1 minute.
Reducing sugars—
To 2 mL of the solution add 5 mL of
alkaline cupric tartrate TS: no reduction occurs at room temperature, and only slight reduction occurs after 1 minute of boiling.
Calcium—
Heat 10.0 g in 100 mL of water to dissolve. Cool to room temperature, add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue, and titrate with 0.05 M edetate disodium VS to a blue endpoint. Not more than 5.0 mL is required: not more than 0.10% calcium is found.
Sulfate 221—
A 1.0 g portion shows no more sulfate than corresponds to 0.5 mL of 0.020 N sulfuric acid (0.05%).
[NOTE—Inulin should be dissolved in 30 to 40 mL of water with gentle warming, prior to dilution to final volume.
]
Heavy metals 231—
Dissolve 4.0 g in 20 mL of boiling water, allow to cool, and dilute with water to 25 mL: the limit is 5 ppm.
Free fructose—
Blue tetrazolium solution—
Dissolve 50 mg of blue tetrazolium in 10 mL of alcohol, and mix.
Standard stock solution—
Prepare an aqueous solution having a known concentration of about 250 µg of
USP Fructose RS per mL. Store at about 4
.
Standard preparation—
On the day of use, quantitatively dilute a portion of the
Standard stock solution with alcohol to obtain a solution having a known concentration of about 2.5 µg per mL. Store at about 4
.
Test preparation—
Transfer about 2.5 g of Inulin, accurately weighed, to a 100-mL volumetric flask, add about 75 mL of water, heat on a steam bath until solution is complete, cool to room temperature, dilute with water to volume, and mix. Pipet 1 mL into a 100-mL volumetric flask, dilute with alcohol to volume, and mix. If the solution is turbid, pass through fine-porosity filter paper.
Procedure—
Pipet 10 mL of the
Test preparation and 10 mL of the
Standard preparation into separate glass-stoppered centrifuge tubes. Into each of the tubes, and into a similar tube containing 10.0 mL of alcohol to provide the blank, pipet 1 mL of
Blue tetrazolium solution, and mix. Then into each tube pipet 1 mL of
Tetramethylammonium hydroxide solution, mix, and allow to stand in the dark for 60 minutes. Without delay, concomitantly determine the absorbances of the solutions from the
Test preparation and the
Standard preparation at 530 nm, with a suitable spectrophotometer, against the blank. Calculate the percentage,
F, of free fructose in the Inulin taken by the formula:
F = (C/W)(AU / AS),
in which
C is the concentration, in µg per mL, of
USP Fructose RS in the
Standard preparation; W is the quantity, in g, of Inulin taken; and
AU and
AS are the absorbances of the solutions from the
Test preparation and the
Standard preparation, respectively. The limit is 2.0%, calculated on the dried basis.
Content of combined glucose—
Standard stock solution—
Transfer about 50 mg of
USP Dextrose RS, accurately weighed, to a 100-mL volumetric flask, dissolve in a solution of benzoic acid (1.7 in 1000), dilute with the same solution to volume, and mix. Allow to stand at room temperature for not less than 3 hours before using. This solution is stable for 1 month at about 4
.
Standard preparation—
Pipet 7 mL of Standard stock solution into a 100-mL volumetric flask, dilute with water to volume, mix, and use at once.
Assay preparation—
Transfer about 0.5 g of Inulin, accurately weighed, to a 100-mL volumetric flask, add 5.0 mL of water, dissolve by heating on a steam bath, cool to room temperature, add 0.5 mL of 8 N hydrochloric acid, and mix. Place the flask in a boiling water bath for 5 minutes, cool, dilute with water to volume, and mix. Pipet 2 mL of this solution into a 10-mL volumetric flask, dilute with water to volume, and mix. [NOTE—This solution is used also for preparing the Assay preparation in the Assay for inulin.]
Procedure—
Pipet 3-mL portions of glucose oxidase–chromogen TS into 3 separate test tubes, and bring to a temperature of 37 ± 0.5
in a water bath. Pipet 2 mL of
Standard preparation into one of the tubes, pipet 2 mL of
Assay preparation into another, and pipet 2 mL of water into the third tube to provide the blank. Maintain at 37 ± 0.5
for an additional 10 minutes, then remove the tubes, and allow them to cool. Determine the absorbances of the solutions from the
Assay preparation and the
Standard preparation at about 505 nm, with a suitable spectrophotometer, using the reagent blank as a reference. Calculate the percentage of combined glucose,
G, in the Inulin taken by the formula:
G = 50(C/W)(AU / AS),
in which
C is the concentration, in mg per mL, of
USP Dextrose RS in the
Standard preparation; W is the amount, in g, of Inulin taken; and
AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively. Not less than 2.0% and not more than 5.0%, calculated on the dried basis, is found.
Assay for inulin—
Thiobarbituric acid solution—
Dissolve 250 mg of thiobarbituric acid in 100 mL of 8 N hydrochloric acid, and mix. This solution is stable for 2 weeks at a temperature of about 4
.
Standard stock solution—
Quantitatively dissolve an accurately weighed quantity of
USP Fructose RS in an aqueous solution of benzoic acid (1.7 in 1000) to obtain a solution having a known concentration of about 1 mg of
USP Fructose RS per mL.
[NOTE—This solution is stable for 1 month at about 4
.
]
Standard preparation—
Quantitatively dilute the Standard stock solution with water to one-fiftieth of its concentration. Use immediately.
Assay preparation—
Pipet 4 mL of the Assay preparation from the Content of combined glucose into a 200-mL volumetric flask, add water to volume, and mix.
Procedure—
Pipet 1-mL portions of the
Standard preparation and the
Assay preparation into separate glass-stoppered tubes. Pipet 1 mL of water into a third tube to provide the blank. Pipet 5-mL portions of
Thiobarbituric acid solution into each tube, and mix. Place all of the tubes simultaneously in a water bath maintained at a temperature of about 83
, and allow them to stay immersed for 5 minutes, accurately timed. Remove the tubes simultaneously, and allow them to cool in a dark place for 30 minutes. Determine the absorbances of the solutions from the
Assay preparation and the
Standard preparation at about 435 nm, with a suitable spectrophotometer, using the reagent blank as a reference. Calculate the percentage of C
6H
11O
5(C
6H
10O
5)
nOH in the Inulin taken by the formula:
0.900[2.5(
C/
W)(
AU /
AS)
F] +
G,
in which 0.900 is the ratio of the formula weight of an anhydrofructose unit of inulin to that of fructose;
C is the concentration, in µg per mL, of
USP Fructose RS in the
Standard preparation; W is the quantity, in g, of Inulin weighed for the
Content of combined glucose; AU and
AS are the absorbances of the solutions from the
Assay preparation and the
Standard preparation, respectively;
F is the percentage of free fructose; and
G is the percentage of combined glucose.
;)
