Potassium Bitartrate CAS 868-14-4 Purity 99.0%~101.0%

Potassium Bitartrate
C4H5KO6 188.18
Butanedioic acid 2,3-dihydroxy-, [R-(R*,R*)]-, monopotassium salt;
Potassium hydrogen tartrate [868-14-4].
DEFINITION
Potassium Bitartrate, dried at 105 for 3 h, contains NLT 99.0% and NMT 101.0% of C4H5KO6.
IDENTIFICATION
• A. Ignite it: it leaves a residue that imparts a reddish purple color to a nonluminous flame.
• B. A saturated solution of it yields a yellowish orange precipitate with sodium cobaltinitrite TS.
• C. Identification Tests-General, Tartrate 191
Sample solution: 1 in 10 solution
Acceptance criteria: Meets the requirements
ASSAY
• Procedure
Sample: Dry 6 g of Potassium Bitartrate at 105 for 3 h. Allow to cool, and weigh.
Analysis: Dissolve the Sample in 100 mL of boiling water, add a few drops of phenolphthalein TS, and titrate with 1 N sodium hydroxide VS to a pink endpoint. Perform a blank determination (see Titrimetry 541). Each mL of 1 N sodium hydroxide is equivalent to 188.2 mg of C4H5KO6.
Acceptance criteria: 99.0%-101.0% on the previously dried basis
IMPURITIES
• Insoluble Matter
Sample: 500 mg
Analysis: Mix the Sample with 3 mL of 6 N ammonium hydroxide.
Acceptance criteria: No undissolved residue remains.
• Limit of Ammonia
Sodium hypochlorite solution: Use a commercially available solution that contains 4.0%-6.0% of sodium hypochlorite.
Oxidizing solution: [Note-Prepare on the day of use.] Alkaline sodium citrate TS and Sodium hypochlorite solution (4:1)
Diluted sodium nitroferricyanide solution: Sodium nitroferricyanide TS and water (1:10)
Standard stock solution: Dry 300 mg of ammonium chloride over silica gel for 4 h, and use it to prepare a 0.3 mg/mL solution in water. This solution contains 100 µg/mL of ammonia.
Standard solution: 0.25 µg/mL of ammonia in water, from Standard stock solution
Sample solution: 2.5 mg/mL of Potassium Bitartrate in water. Heat gently to facilitate the dissolution.
Analysis
[Note-Carefully follow the order of addition stated below. ]
Separately transfer 6.0 mL each of the Standard solution and the Sample solution to two color-comparison tubes. To each tube add 0.4 mL of phenol TS, 0.4 mL of Diluted sodium nitroferricyanide solution, and 1.0 mL of Oxidizing solution. Dilute with water to 10 mL, mix, and allow to stand for 1 h.
Acceptance criteria: The color of the Sample solution is not darker than the color of the Standard solution (NMT 0.01%).
• Heavy Metals, Method II 231: NMT 20 ppm
ADDITIONAL REQUIREMENTS
• Packaging and Storage: Preserve in tight containers.