Potassium Sorbate
C6H7KO2 150.22
2,4-Hexadienoic acid, (E,E)-, potassium salt;
2,4-Hexadienoic acid, potassium salt;
Potassium (E,E)-sorbate;
Potassium sorbate
[590-00-1; 24634-61-5].
(poe tas' ee um sor' bate).
+'&img=../../images/v35300/g-1160.gif&casNumber=590-00-1&usp=35&nf=30&chemicalStructureImage=true&ID='+parent.myID,600,500);)
C6H7KO2 150.22
2,4-Hexadienoic acid, (E,E)-, potassium salt;
2,4-Hexadienoic acid, potassium salt;
Potassium (E,E)-sorbate;
Potassium sorbate
[590-00-1; 24634-61-5].DEFINITION
Potassium Sorbate contains NLT 98.0% and NMT 101.0% of C6H7KO2, calculated on the dried basis.
IDENTIFICATION
• A. Identification Tests—General, Potassium 
191
191
Sample:
Dissolve 1 g of Potassium Sorbate in 10 mL of water.
Acceptance criteria:
Meets the requirements
• B.
Sample:
0.2 g of Potassium Sorbate
Analysis:
Dissolve the Sample in 2 mL of water, and add a few drops of bromine TS.
Acceptance criteria:
The color is discharged.
ASSAY
• Procedure
Sample:
300 mg of Potassium Sorbate
Blank:
40 mL of glacial acetic acid
Titrimetric system
(See Titrimetry 541.)
541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Endpoint detection:
Visual
Analysis:
Dissolve the Sample in 40 mL of glacial acetic acid, warming, if necessary, to dissolve the solution. Cool to room temperature, and add 1 drop of crystal violet TS. Titrate with Titrant to a blue-green endpoint. Perform a blank determination.
Calculate the percentage of potassium sorbate (C6H7KO2) in the Sample taken:
Result = {[(VS 
VB) × N × F]/W} ×100
VB) × N × F]/W} ×100| VS | = | = Titrant consumed by the Sample (mL) |
| VB | = | = Titrant consumed by the Blank (mL) |
| N | = | = actual normality of the Titrant (mEq/mL) |
| F | = | = equivalency factor, 150.2 mg/mEq |
| W | = | = Sample weight (mg) |
Acceptance criteria:
98.0%–101.0% on the dried basis
IMPURITIES
• Heavy Metals, Method II 231:
NMT 10 ppm
231:
NMT 10 ppm
SPECIFIC TESTS
• Acidity or Alkalinity
Sample solution:
1.1 g of Potassium Sorbate in 20 mL of water
Analysis:
Add phenolphthalein TS to the Sample solution.
Acceptance criteria:
If the solution is colorless, titrate with 0.10 N sodium hydroxide to a pink color that persists for 15 s: NMT 1.1 mL of 0.10 N sodium hydroxide is required. If the solution is pink in color, titrate with 0.10 N hydrochloric acid to discharge the pink color: NMT 0.80 mL of 0.10 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.
731:
Dry a sample at 105 for 3 h: it loses NMT 1.0% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight containers, protected from light, and avoid exposure to excessive heat.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Robert H. Lafaver, M.S.
Scientific Liaison 1-301-816-8335 |
(EXC2010) Monographs - Excipients |
USP35–NF30 Page 1929