Authorization for Use as Food Additives (P otassium Lactate and Potassium Sulfate) 
and revision specifications for 5-methylquinoxaline  The government of Japan will designate Pota ssium Lactate and Potassium Sulfate as 
authorized food additives, and revise specifications for 5-methylquinoxaline. 
 Summary
 
Under Article 10 of the Food Sanitation Law,  food additives may not be used marketed 
without the authorization by the Minister  of Health, Labour and Welfare. Where 
standards for use of additives and/or their compositional specifications are established 
based on Article 11 of the law, those additives may not be used or marketed when they do not meet these standards and/or specifications.    In response to a request from the Minist er of Health, Labour and Welfare, the 
Committee on Food Additives of the Food Sanitation Council that is established under the Pharmaceutical Affairs and Food Sanitation Council has discussed the adequacy of the designation of Potassium Lactate and Potassium Sulfate
 as food additives, and the 
specifications for 5-methylquinoxaline. Th e conclusion of the committee is outlined 
below.     Outline of conclusion 
 
The Minister of Health, Labour and Welfare, based on Article 10 of the Food Sanitation 
Law, should designate Potassium Lactate an d Potassium Sulfate, as food additives 
unlikely to harm human health, and establis h compositional specifications, based on 
Article 11 of the law (see Attachments 1 and 2). Also, the Minister should revise the specifications for 5-methylquinoxaline, based on Article 11 of the law (see Attachments 
3 ).     Attachment 1 
 
Potassium Lactate 
COOK
OHH3C
 
 
 
Standard for use  
Not established.   
           
  
Compositional specifications  
Substance name   Potassium Lactate       
Molecular formula   C 3H5KO 3 
Mol. Weight   128.17 
Chemical name [CAS number]    
Monopotassium 2-hydroxyp ropanoate  [996-31-6] 
Content  Potassium Lactate contains not le ss than 50.0% of potassium lactate 
(C3H5KO 3) and the equivalent of 95 −110% of the labeled content.  
Description   Potassium Lactate is a colorless, clear,  slightly viscose liquid. It is odorless 
or has a slight characteristic odor.        Identification   Potassium Lactate responds to all tests for Potassium Salt and Lactate 
in the Qualitative Tests.   
Purity   
(1) Free acid
  Weigh exactly an amount of Potassium Lactate equivalent to 0.60 g 
of potassium lactate, add 20 ml of freshly boiled and cooled water and 3 drops of phenolphthalein TS, and titrate with 0.1 mol/ L sodium hydroxide. Its consumption is 
not more than 0.2 ml.   
(2)  Lead
  Not more than 2.0 g/g as Pb for 60% potassium lactate. 
Test Solution  Weigh an amount of Potassium Lactate equivalent to 3.0 g of 
potassium lactate, place to a cr ucible, and add 2 ml of sulfuric acid little by little. Heat 
gradually at as low temperature as possi ble until the sample in the crucible is 
carbonized and white fumes are no longer evolved. Place the crucible in an electric muffle, and ignite at 450 −550ºC until the sample is calcifie d. To the residue, add 10 ml 
of diluted hydrochloric acid (1 in 4), and heat  to dryness on a water bath. To the residue, 
add diluted nitric acid (1 in 150), dissolv e by ultrasonic treatment, and add diluted nitric acid (1 in 150) again to make exactly 10 ml.  
Control Solution  Measure exactly 1 ml of Lead Standard Solution, and add 
diluted nitric acid (1 in 150) to make exactly 10 ml.  
Procedure   For the test solution and the control solution, proceed as directed in 
Method 1 in the Lead Limit Test. 
(3)  Arsenic   Not more than 4.0 g/g as  As 2O3. 
Test Solution  Weigh an amount of Potassium Lactate equivalent to 0.60 g of 
potassium lactate, and add water to make 10 ml . Use 5 ml of this solution as the test 
solution.  
Apparatus   Use Apparatus B. 
(4) Reducing substances   Add 5 drops of Potassium Lactate to 10 ml of Fehling’s 
TS, and boil for 5 minutes. No red precipitate is produced.  
Assay  Weigh accurately an amount of Potassium  Lactate equivalent to about 0.3 g of 
potassium lactate, and evaporate to dryness. To the residue, add 60 ml of a 5:1 mixture of acetic acid/acetic anhydride, dissolve comp letely, and titrate with 0.1 mol/L perchloric 
acid. Usually, a 
potentiometer is used to confirm the endpoint. When crystal 
violet-acetic acid TS (1 ml) is used as the indicator, the endpoint is when the color of the 
solution changes from violet through blue to  green. Separately pe rform a blank test to 
make necessary correction.          Each ml of 0.1 mol/L perchloric acid = 12.82 mg of C
3H5KO 3 
  Attachment 2 
 
Potassium Sulfate 
  
Standard for use 
 
Not established.  
  Compositional specifications 
 
Substance name   Potassium Sulfate      
Molecular formula   K 2SO 4 
Mol. Weight   174.26 
Chemical name [CAS number]    
Potassium sulfate  [7778-80-5] 
Content  Potassium Sulfate contains not less than 99.0% of potassium sulfate (K 2SO 4). 
Description   Potassium Sulfate occurs as colo rless or white crystals or crystalline 
p o w d e r .       Identification    
Potassium Sulfate responds to all tests for Potassium Salt and Sulfate in the 
Qualitative Tests.   
Purity    
(1) pH
  5 . 5−8.5 (1.0 g, water 20 ml). 
(2) Lead   Not more than 2.0 g/g as Pb. 
Test Solution  Weigh exactly  5.0 g of  Potassium Sulfate in a 100-ml beaker, and 
dissolve it in 40 ml of diluted hydrochloric acid (1 in 4). Cover the beaker with a watch 
glass, boil for 5 minutes, and cool. Designate this solution as the sample solution. To the sample solution, add 10 ml of a solution of dia mmonium hydrogen citrate (1 in 2), and 
make weekly alkaline with ammo nia solution using thymol blue TS as an indicator. 
After cooling, transfer the re sulting solution to a 200-ml separating funnel. Wash the 
beaker with water and add the washings to th e separating funnel to make about 100 ml.  
Add 5 ml of a solution of ammonium pyrrolid ine dithiocarbamate (3 in 100), and allow to 
stand for 5 minutes.  Add 10 ml of butyl acetate, agitate for 5 minutes, and allow to tand. Use the butyl acetate layer as the test solution.        
Control Solution   Measure exactly 1 ml of Lead St andard Solution, and add water 
to make exactly 100 ml. Measure exactly 10 ml of this solution, and proceed in the same 
manner as for the sample solution.     Procedure   For the test solution and the control solution, proceed as directed in 
Method 1 in the Lead Limit Test. 
(3) Selenium  Not more than 30 g/g. 
Test solution and control solution   Place 0.20 g of Potassium Sulfate in a beaker, 
add 25 ml of hydrochloric acid TS (4 mol/ L), shake, and add 25 ml of water. Designate 
this solution as the sample solution. 
Measure exactly 3 ml of Selenium Stan dard Solution, and add water to make 
exactly 1000 ml. Measure exactly 2 ml o f this solution in a beaker, and add 50 ml of 
hydrochloric acid TS (2 mol/L). Designate th is solution as the control stock solution.  
Carefully add 5 ml of ammonia solution to each of the sample solution and control 
stock solution. Do this step in a draft chamber. After cooling, adjust the pH of each solution to 1.8 −2.2 with diluted ammonia solution (1 in 2), and add water to make 60 ml 
each. Transfer them to separate separating funnels, wash each beaker with 10 ml of water, and add the washings to each separating funnel. Add 0.2 g of hydroxylammonium chloride to each, and di ssolve while gently shaking. Add 5 ml of 
2,3-diamononaphthalene TS, shake, and a llow to stand for 100 minutes. To each, add 
5.0 ml of cyclohexane, shake well for 2 minutes. Collect the cyclohexane layers, separately centrifuge at 3000 rmp for10 minut es. Use the upper layers of them as the 
test solution and control solution, respectively.  
Procedure  Measure the absorbance of th em at the maximum absorption 
wavelength around 378 nm against a reference that is prepared using 50 ml of 
hydrochloric acid TS (2 mol/L) in the same manner as for the sample solution. The 
absorbance of the test solution is not greater than that of the control solution.      
(4) Arsenic   Not more than 4.0 g/g as  As 2O3  (0.50 g, Method 1, Apparatus B).        
Assay  Weigh accurately about 0.5 g of Potassium Sulfate, dissolve it in 200 ml of water, 
add 1 ml of hydrochloric acid, and boil. Add 8 ml of barium chloride solution (3 in 25) 
little by little while stirring, and heat on a wa ter bath for 1 hour. After cooling, filter the 
solution through a filter paper for quantita tive analysis (5C), and wash the residue on 
the filter paper with water until the washing no longer shows chloride reaction. Place 
the filter paper with residue in a crucible,  already ignited and weighed, dry it, and 
ignite at 500 −600ºC to constant weight. Weigh accura tely the residue, and calculate the 
content by the formula:     
Content ሺ%ሻ of potassium sulfate ሺK ଶSOସሻൌ 
Weight ሺgሻ of the residueൈ   0.7466 
Weight ሺgሻ of the sampleൈ100  
  
Regents and Solutions  
Sodium Selenite  Na 2SeO 3   A white crystalline powder. Soluble in water.    
Content   Not less than 97.0%.  
   Purity  (1) Solubility of solution  Clear (2.0 g, water 20 ml). 
(2) Selenium salt and sulfate   Measure exactly 5 ml of the test solution prepared in (1), 
add 10 ml of water, and adjust the pH to 6. 0 with diluted hydrochloric acid (1 in 3). Add 
1 ml of diluted hydrochloric acid (2 in 3) , and add water to make exactly 25 ml. To the 
resulting solution, add 2 ml of barium chloride  solution (1 in 10), and allow to stand for 
30 minutes. The solution is not turbid.  
Assay   Weigh accurately about 1 g of Sodi um Selenium, and dissolve in water to 
make exactly 200 ml. Transfer exactly measur ed 20 ml of this solution to a 200-ml 
iodine flask or a 200-ml Erlenmeyer flask with a ground glass stopper. Add 80 ml of 
water, 3 g of potassium iodide, and 5 ml of diluted hydrochloride acid (2 in 3). Immediately stopper, allow to stand for 5 minutes  in a dark place. Titrate the free iodine 
with 0.1 mol/L sodium thiosulf ate using 0.5 ml of starch TS as the indicator.  
Separately, perform a blank test to make ne cessary correction. Starch TS should be 
added when the color of the solution becomes light yellow near endpoint. The endpoint is when the blue color of solution disappears.     
Each ml of 0.1 mol/L sodium thiosulfate = 4.324 mg of Na
2SeO 3  
Hydrochloric Acid TS (2 mol/L)   Measure 180 ml of hydrochl oric acid, and add water to 
make 1000 ml.  
Hydrochloric Acid TS (4 mol/L)   Measure 360 ml of hydrochl oric acid, and add water to 
make 1000 ml.  
Nitric Acid TS (0.1 mol/L)  Measure 6.4 ml, 6.9 ml, or 7. 6 ml of nitric acid whose 
concentration is 69 −70%, 65−66%, or 60 −61%, whichever is appropriate, and add water 
to make 1000 ml.   
Standard Solutions  
Selenium Standard Solution  Weigh 2.19 g, add nitric acid  TS (0.1 mol/L) to make 
exactly1000 ml. Each ml of this solution contains 1 mg of selenium (Se).   
  Attachment 3 
 
5-Methylquinoxaline 
 
 
 
Compositional specifications  
Substance name   5-Methylquinoxaline     
Molecular formula   C 9H8N2  
Mol. Weight   144.17 
Chemical name [CAS number]    
5-Methylquinoxaline  [ 13708-12-8 ] 
Content  5-Methylquinoxaline contains not less  than 98.0% of 5-methylquinoxaline 
(C9H8N2). 
Description  5-Methylquinoxaline occurs as a colorless to orange-color liquid or 
crystalline lumps having a characteristic odor. 
Identification   Determine the infrared absorption spectrum of 5-Methylquinoxaline  
as directed in the Liquid Film Method under Infrared Spectrophotometry, and compare with the Reference Spectrum. Both spectra ex hibit absorptions having about the same 
intensity at the same wavenumbers. Purity   
(1) Refractive index
  n20
D: 1.615–1.625.   
(2) Specific gravity   d25
25: 1.102 –1.128 . 1.102−1.132.  
Assay  Proceed as directed in the Peak Area Percentage Method in the Gas 
Chromatographic Assay under the Flavor Substa nce Tests. Use operating conditions (1).