Attachment 
Potassium Hydrogen Carbonate 
炭酸水素カリウム 
 
Standards for Use  
Permitted for use in grape juice used for wine production and in grape wine only. 
 
Compositional Specifications 
Substance Name  Potassium Hydrogen Carbonate (Potassium Bicarbonate, Potassium 
Acid Carbonate) 
Molecular Formula  KHCO3 
Molecular Weight  100.12 
Chemical Name [CAS number] 
Potassium hydrogen carbonate [298-14-6] 
Content  Potassium Hydrogen Carbonate, when dried, contains not less than 99.0% of 
potassium hydrogen carbonate (KHCO3). 
Description  Potassium Hydrogen Carbonate occurs as colorless crystals, or as white 
granules or powder. 
Identification  Potassium Hydrogen Carbonate responds to all the tests for Potassium 
Salt and for Bicarbonate in the Qualitative Tests. 
Purity 
(1) Clarity of solution  Almost clear (1.0 g, water 10 mL). 
(2) Lead  Not more than 2 μg/g as Pb (2.0 g, Method 5, Control Solution: Lead 
Standard Solution 4.0 mL, Flame Method). 
Sample Solution  To the specified amount of Potassium Hydrogen Carbonate, add 20 
mL of diluted hydrochloric acid (1 in 4), and boil gently for 5 minutes with a watch glass 
covering it. Allow to cool, and use the solution as the sample solution. If the sample does 
not dissolve completely, evaporate it to dryness, and add 20 mL of diluted hydrochloric 
acid (1 in 4) to the residue. Boil gently for 5 minutes, and allow to cool. 
(3) Arsenic  Not more than 3 μg/g as As (0.50 g, Standard Color: Arsenic Standard 
Solution 3.0 mL, Apparatus B). 
Test Solution  Weigh the specified amount of Potassium Hydrogen Carbonate, and dissolve it by adding 3 mL of water and 2 mL of hydrochloric acid. 
Loss on Drying  Not more than 0.25% (4 hours). 
Assay  Weigh accurately about 2 g of Potassium Hydrogen Carbonate, previously dried, 
dissolve it in 25 mL of water, and titrate with 0.5 mol/L sulfuric acid (indicator: 3 drops 
of bromophenol blue TS). Boil near the endpoint to let the carbon dioxide out, cool, and 
continue the titration. The endpoint is when the color of the solution changes from blue-
purple to bluish-green. 
Each mL of 0.5 mol/L sulfuric acid = 100.1 mg of KHCO3 
 