Fructose

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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C₆H₁₂O₆ 180.16

d-Fructose CAS RN®: 57-48-7.

1 DEFINITION

Fructose, dried under vacuum at 70° for 4 h, contains NLT 98.0% and NMT 102.0% of Fructose (C₆H₁₂O₆).

2 IDENTIFICATION

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K

Sample: Previously dried

Acceptance criteria: Meets the requirements

3 ASSAY

Procedure

Sample: 10 g, previously dried

Optical rotation

(See Optical Rotation 〈781〉, Procedures, Angular Rotation.)

Tube length: 100 mm

Temperature: 25°

Analysis: Transfer the Sample to a 100-mL volumetric flask, and dissolve in 50 mL of water. Add 0.2 mL of 6 N ammonium hydroxide, and dilute with water to volume. After 30 min, determine the angular rotation. The observed rotation, in degrees, represents the weight, in g.

Calculate the percentage of fructose (C₆H₁₂O₆) in the portion of Fructose taken.

Result = [(a × F)/W] × 100

a = observed rotation of the sample (°)

F = correction factor, −1.124

W = weight of the Sample (g)

Acceptance criteria: 98.0%–102.0% on a previously dried basis

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.5%

Chloride and Sulfate 〈221〉, Chloride

Sample: 2.0 g

Control: 0.50 mL of 0.020 N hydrochloric acid

Acceptance criteria: NMT 0.018%; the Sample shows no more chloride than corresponds to the Control.

Chloride and Sulfate 〈221〉, Sulfate

Sample: 2.0 g

Control: 0.50 mL of 0.020 N sulfuric acid

Acceptance criteria: NMT 0.025%; the Sample shows no more sulfate than corresponds to the Control.

Delete the following:

Arsenic 〈211〉, Method II

Test preparation: Prepare by heating the acidified mixture nearly to dryness. Cool, and add 30% Hydrogen peroxide.

Acceptance criteria: NMT 1 μg/g (USP 1-May-2022)

Calcium and Magnesium (as Calcium)

Sample: 20 g

Titrimetric system

Mode: Direct titration

Titrant: 0.005 M edetate disodium VS

Endpoint detection: Visual

Analysis: Dissolve the Sample in 200 mL of water. Add 2 drops of hydrochloric acid, 5 mL of ammonia–ammonium chloride buffer TS, and 8 drops of eriochrome black TS, and mix. Titrate with Titrant to a blue endpoint. Each mL of Titrant is equivalent to 200.4 μg of Ca.

Acceptance criteria: 0.005% of Ca; NMT 5.0 mL of Titrant is consumed.

Limit of Hydroxymethylfurfural

Resorcinol solution: 10 mg/mL of resorcinol in hydrochloric acid

Sample solution: 100 mg/mL

Analysis: To 10 mL of Sample solution add 5 mL of ethyl ether, and shake vigorously. Transfer 2 mL of the ether layer to a test tube, and add 1 mL of Resorcinol solution.

Acceptance criteria: A slight pink color may develop, but no cherry-red color appears immediately.

5 SPECIFIC TESTS

5.1 Color of Solution

Sample solution: 25 g of Fructose in water to make 50 mL

Comparison solution: Mix 1.0 mL of cobaltous chloride CS, 3.0 mL of ferric chloride CS, and 2.0 mL of cupric sulfate CS with water to make 10 mL, and dilute 3 mL of this solution with water to make 50 mL.

Analysis: View the Sample solution and Comparison solution downward in matched color-comparison tubes against a white surface.

Acceptance criteria: The Sample solution has no more color than the Comparison solution.

5.2 Acidity

Sample: 5.0 g

Titrimetric system

Mode: Direct titration

Titrant: 0.02 N sodium hydroxide VS

Endpoint detection: Visual

Analysis: Dissolve the Sample in 50 mL of carbon dioxide-free water. Add phenolphthalein TS, and titrate with Titrant to a distinct pink color.

Acceptance criteria: NMT 0.50 mL of Titrant is needed for neutralization.

5.3 Loss on Drying

Analysis: Dry under vacuum at 70° for 4 h.

Acceptance criteria: NMT 0.5%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Fructose RS