ACESULFAME POTASSIUM 

 

 

Prepared at the 57th JECFA (2001) and published in FNP 52 Add 9 
(2001), superseding specifications prepared at the 46th JECFA (1996) and 
published in FNP 52 Add 4 (1996). An ADI of 0-15 mg/kg body weight was 
established at the 37th JECFA (1990). 

 

SYNONYMS  

Acesulfame K; INS No. 950 
 

DEFINITION  

 
 

Chemical names  

Potassium salt of 6-methyl-1,2,3-oxathiazine-4(3H)-one-2,2-dioxide; 
potassium salt of 3,4-dihydro-6-methyl-1,2,3-oxathiazine-4-one-2,2-dioxide
 

C.A.S. number  

55589-62-3 
 

Chemical formula  

C

4

H

4

KNO

4

S 

 

Structural formula  

 

Formula weight  

201.24 
 

Assay 

Not less than 99.0% and not more than 101.0% on the dried basis 
 

DESCRIPTION  

Odourless, white crystalline powder 
 

FUNCTIONAL USES 

Sweetener, flavour enhancer 
 

CHARACTERISTICS 

 
 

IDENTIFICATION 

 
 

Solubility (Vol. 4) 

Freely soluble in water, very slightly soluble in ethanol 
 

Spectrophotometry 

Dissolve 10 mg of the sample in 1,000 ml of water. The solution shows an 
absorbance maximum at 227±2 nm 
 

Test for potassium  
(Vol.4) 

Passes test 
Test the residue obtained by igniting 2 g of the sample 
 

Precipitation test 

Add a few drops of a 10% solution of sodium cobaltinitrite to a solution of 
0.2 g of the sample in 2 ml of acetic acid TS and 2 ml of water. A yellow 
precipitate is produced. 
 

PURITY 

 
 

Loss on drying (Vol. 4) 

Not more than 1.0% (105

o

, 2 h) 

pH (Vol. 4) 

5.5 - 7.5 (1% soln) 
 

Organic impurities 

Passes test for 20 mg/kg of UV active components 
See description under TESTS 
 

Fluoride (Vol. 4) 

Not more than 3 mg/kg 
Method III; using an appropriate sample size and appropriate volumes of 
the standard solution for construction of the calibration curve. 
 

Lead (Vol. 4) 

Not more than 1 mg/kg 
Determine using an atomic absorption technique appropriate to the 
specified level. The selection of sample size and method of sample 
preparation may be based on the principles of the method described in 
Volume 4, “Instrumental Methods.” 
 

TESTS 

 
 

PURITY TESTS 

 
 

Organic impurities 

Proceed as directed under the method for Chromatography (High 
Performance Liquid Chromatography, FNP 5) using the following 
conditions and using 4-hydroxybenzoic acid ethyl ester as the reference 
substance: 
 
Column: 25 cm x 4.6 mm stainless steel 
Stationary phase: Reversed phase (C18 silica gel, 3 - 5 µm) 
Elution: Isocratic 
Mobile phase: Acetonitrile/0.01 mol/l tetrabutyl ammonium hydrogen 
sulfate (TBAHS) in water; 40/60 v/v  
Flow: About 1 ml/min 
Detector type: UV or Diode array, 227 nm 
Sample size: 20 µl of a 10 g/l solution of the sample in deionized water 
 
The chromatographic system must be capable of separating acesulfame K 
and 4-hydroxybenzoic acid ethyl ester with a resolution of 2. 
If peaks other than that due to acesulfame K appear within three times the 
elution time of acesulfame K, carry out a second run using 20 µl of a 0.2 
mg/l solution of the sample. 
 
The sum of the areas of all peaks eluted in the first run within 3 times the 
elution time of acesulfame K elution time, except for the acesulfame K 
peak, does not exceed the peak area of acesulfame K in the second run. 
 

METHOD OF 
ASSAY 

Dissolve about 0.15 g of the dried sample (dissolution may be slow), 
accurately weighed, in 50.0 ml glacial acetic acid and titrate 
potentiometrically with 0.1 N perchloric acid, or add two drops of crystal 
violet TS and titrate with 0.1 N perchloric acid, to a blue-green end-point 
which persists for at least 30 sec. Perform a blank determination and make 
any necessary correction. Each ml of 0.1 N perchloric acid is equivalent to 
20.12 mg of C

4

H

4

KNO

4

S.