Acesulfame K CAS 55589-62-3 Acesulfame Potassium Purity >99.0% (HPLC)

DEFINITION
Acesulfame Potassium contains NLT 99.0% and NMT 101.0% of C4H4NO4SK, calculated on the dried basis.
IDENTIFICATION
• A. INFRARED ABSORPTION <197K>
• B. IDENTIFICATION TESTS-GENERAL, Potassium <191>
Sample solution: 100 mg/mL
Acceptance criteria: Meets the requirements
ASSAY
• PROCEDURE
Sample: 150 mg
Titrimetric system (See Titrimetry <541>)
Mode: Direct titration
Titrant: 0.1 N perchloric acid VS
Blank: 50 mL of glacial acetic acid
Endpoint detection: Potentiometric
Analysis: Dissolve the Sample in 50 mL of glacial acetic acid.
Titrate with 0.1 N perchloric acid VS. Perform a blank determination.
Calculate the percentage of acesulfame potassium (C4H4NO4SK) in the Sample:
Result = [(V − B) × N × F × 100]/W
V = titrant volume consumed by the Sample (mL)
B = titrant volume consumed by the Blank (mL)
N = titrant actual normality (mEq/mL)
F = equivalency factor, 201.2 mg/mEq
W = weight of Sample (mg)
Acceptance criteria: 99.0%–101.0% on the dried basis
IMPURITIES
• LIMIT OF FLUORIDE
[NOTE-Use plasticware throughout this test.]
Solution A: Dissolve 210 g of citric acid monohydrate in 400 mL of water. Adjust with concentrated ammonia to a pH of 7.0, and dilute with water to 1000 mL.
Solution B: 132 mg/mL of dibasic ammonium phosphate
Solution C: To a suspension of 292 g of edetic acid in 500 mL of water, add 200 mL of ammonium hydroxide, adjust with ammonium hydroxide to a pH between 6 and 7, and dilute with water to make 1000 mL.
Buffer solution: Mix equal volumes of Solution A, Solution B and Solution C, and adjust with ammonium hydroxide to a pH of 7.5.
Standard stock solution: Weigh 0.442 g of sodium fluoride, previously dried at 300° for 12 h, into a 1-L volumetric flask, and dilute with water to volume. Store the solution in a closed plastic container. Immediately before use, pipet 5 mL of this solution into a 100-mL volumetric flask, and dilute with water to volume. Each mL of this solution contains 10µg of fluoride ion.
Standard solution A: Mix 0.5 mL of Standard stock solution and 15.0 mL of Buffer solution, and dilute with water to 50mL.
Standard solution B: Mix 1.0 mL of Standard stock solution and 15.0 mL of Buffer solution, and dilute with water to 50mL.
Standard solution C: Mix 1.5 mL of Standard stock solution and 15.0 mL of Buffer solution, and dilute with water to 50mL.
Standard solution D: Mix 3.0 mL of Standard stock solution and 15.0 mL of Buffer solution, and dilute with water to 50mL.
Sample solution: To a 50-mL volumetric flask add 3 g of Acesulfame Potassium. Dissolve in water, add 15.0 mL of Buffer solution, and dilute with water to volume.
Analysis
Samples: Standard solution A, Standard solution B, Standard solution C, Standard solution D, and Sample solution
Concomitantly measure the potential (see Titrimetry <541>) in mV, of the Standard solutions and the Sample solution, with a suitable pH meter equipped with a fluoride-specificion electrode and a silver-silver chloride reference electrode. When taking the measurements, transfer the solution to a 25-mL beaker, and immerse the electrodes. Insert a polytef-coated stirring bar into the beaker, place the beaker on a magnetic stirrer having an insulated top and allow to stir until equilibrium is attained (1-2 min). Rinse, and dry the electrodes between measurements, taking care not to scratch the crystal in the fluoride-specific ion electrode. Measure the potential of each Standard solution, and plot the fluoride concentration, in µg/mL, versus the potential, in mV, on semilogarithmic paper. Measure the potential of the Sample solution, and determine the fluoride concentration from the standard curve, in µg/mL.
Calculate the content, in ppm, of fluoride in the portion of Acesulfame Potassium taken:
Result = (V × C/W)
V = volume of the Sample solution (mL)
C = concentration of fluoride in the Sample solution, from the standard curve (mg/mL)
W = weight of Acesulfame Potassium taken to prepare the Sample solution (g)
Acceptance criteria: NMT 3 ppm
• HEAVY METALS, Method I <231>: NMT 10 ppm
• CHROMATOGRAPHIC PURITY
Solution A: 3.3 mg/mL of tetrabutylammonium hydrogen sulfate
Mobile phase: Acetonitrile and Solution A (2:3)
System suitability solution: 2 µg/mL each of USP Acesulfame Potassium RS and ethylparaben
Standard solution: 0.2 µg/mL of USP Acesulfame Potassium RS
Sample solution: 10 mg/mL
Chromatographic system
(See Chromatography <621>, System Suitability.)
Mode: LC
Detector: UV 227 nm
Column: 4.6-mm × 25-cm; 5-µm packing L1
Flow rate: 1 mL/min
Injection size: 20 µL
System suitability
Sample: System suitability solution
Suitability requirements
Resolution: NLT 2 between acesulfame potassium and ethylparaben
Analysis
Samples: Standard solution and Sample solution
Record the chromatograms for a run time NLT 3 times the retention time of the acesulfame potassium peak, and measure the area responses of the peaks.
Acceptance criteria: The response of any peak at a retention time other than that of acesulfame potassium from the Sample solution does not exceed the response of the acesulfame potassium peak from the Standard solution (0.002%).
SPECIFIC TESTS
• ACIDITY OR ALKALINITY
Sample solution: 4.0 g in 20 mL of carbon dioxide-free water
Analysis: Add 0.1 mL of bromothymol blue TS. If the solution is yellow, titrate with 0.01 N sodium hydroxide to produce a blue color. If the solution is blue, titrate with 0.01 N hydrochloride acid to produce a yellow color.
Acceptance criteria: NMT 0.2 mL of 0.01 N sodium hydroxide or NMT 0.2 mL of 0.01 N hydrochloric acid is required.
• LOSS ON DRYING <731>: Dry a sample at 105° for 3 h: it loses NMT 1.0% of its weight.
ADDITIONAL REQUIREMENTS
• PACKAGING AND STORAGE: Preserve in a well-closed container, and protect from light. Store at room temperature.
USP REFERENCE STANDARDS <11>
USP Acesulfame Potassium RS