Attachment 
Dimethyl Dicarbonate 
二炭酸ジメチル 
 
 
Standards for use 
 
Dimethyl Dicarbonate is not permitted to use for food products other than fruit wines 
and nonalcoholic beverages (excluding mineral waters). The amount of Dimethyl 
Dicarbonate shall not be exceeding 0.25 g/kg in fruit wines (excluding grape wine) 
and nonalcoholic beverages, and not be exceeding 0.20 g/kg in grape wine. 
 
 
Compositional specifications 
 
Substance name  Dimethyl Dicarbonate 
Structural formula 
 
 
 
Molecular formula  C4H6O5 
Molecular weight  134.09 
Chemical name [CAS number] 
Dimethyl dicarbonate  [4525-33-1] 
Content  Dimethyl Dicarbonate contains not less than 99.8% of dimethyl 
dicarbonate (C4H6O5). 
Description  Dimethyl Dicarbonate is a colorless liquid. 
Identification test 
Determine the absorption spectrum of Dimethyl Dicarbonate as directed in the 
Liquid Film Method under Infrared Spectrophotometry, and compare with the 
Reference Spectrum. Both spectra exhibit similar intensities of absorption at the 
same wave-numbers.  
 
Purity test 
(1) Lead  Not more than 1 μg/g as Pb (Electrothermal Method). 
Test Solution  Weigh accurately about 1.5 g of Dimethyl Dicarbonate into a 
container made of polyethylene, quartz, or hard-glass, and add 0.75 mL of nitric 
acid (for trace metals determination). Cover its container loosely, heat up gradually 
with stirring or occasional shaking, heat at 90C to 30 minutes, and cool. Add 
dropwise 0.85 mL of hydrogen peroxide, heat at 95C to 5–10 minutes with stirring 
or occasional shaking, and cool. Add dropwise hydrogen peroxide, heat in the same 
manner, and cool. Transfer this solution into a 25-mL volumetric flask, wash the 
container with a small amount of water, combine the washings with the solution, 
and add water to make 25 mL. 
Standard Solutions  Prepare four standard solutions with different 
concentrations. Transfer exactly 1, 2.5, 5, 10 mL of Lead Standard Solution into 
four separate 100-mL volumetric flasks, and to them, add a diluted solution (3 in 
100) of nitric acid (for trace metals determination) to make exactly 100 mL. 
Procedure  Measure exactly a constant portion of the test solution and the 
standard solutions, and to each, add a quarter volume of a solution of magnesium 
nitrate hexahydrate (1 in 50), prepared before use. Analyze 25-μL portions of these 
solutions as directed in Lead Limit Test (Atomic Absorption Spectrophotometry) 
using the operating conditions given below. Determine the concentration (ng/mL) of 
lead in the test solution from the calibration curve prepared using the standard 
solutions. Calculate the amount of lead in the sample by the formula given below. 
Perform a blank test using the blank test solution prepared with water instead of 
Dimethyl Dicarbonate in the same manner as for the test solution, and make any 
necessary correction.  
Amount (μgg)⁄of lead= Concentration (μgmL⁄ ) × 25
Weight (g) of the sample  
 
Operating Conditions 
Light source: Lead hollow cathode lamp. 
Wavelength: 283.3 nm. 
Temperature for drying: A constant temperature of 200–250C. 
Temperature for incineration: A constant temperature of 700–750C. 
Temperature for atomization: A constant temperature of 1800–2000C. 
 
(2) Dimethyl carbonate  Not more than 0.2%.  
 
The procedure given here should be done as quickly as possible in order to avoid 
humidity. 
Test Solution  Weigh accurately about 5 g of Dimethyl Dicarbonate, add 0.5 mL 
of the internal standard solution, and add tert-butyl methyl ether to make exactly 5 
mL. 
Standard Solution  Weigh accurately about 10 mg of dimethyl carbonate, add 
exactly 0.5 mL of the internal standard solution, and add tert-butyl methyl ether to 
make exactly 5 mL. 
Internal Standard Solution  Dissolve 50 mg of 3-pentanone in tert-butyl methyl 
ether to make exactly 5 mL. 
Procedure  Analyze 0.5-μL portions of the test solution and the standard 
solution by gas chromatography using the operating conditions given below. 
Determine the peak area ratios (QT and QS) of dimethyl carbonate to 3-pentanone 
for the test solution and the standard solution, respectively. Determine the amount 
of dimethyl carbonate by the formula: 
Amount (%) of dimethyl carbonate (C3H6O3)
= Weight (mg) of dimethyl carbonate
Weight (g) of the sample × 1000 × Q
Q × 100 
Operating Conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.53 mm internal diameter and 60 m length) 
coated with a 1.5 μm thick layer of dimethylpolysiloxane for gas 
chromatography. 
Column temperature: Maintain the temperature at 45C for 7.5 minutes, 
raise at 10C/minute to 75C, then raise at 25C/minute to 125C, and 
maintain the temperature at 125C for 2 minutes. Raise at 
30C/minute to 260C, and maintain the temperature at 260C for 4.5 
minutes. 
Detector temperature: 300C. 
Carrier gas: Helium. 
Flow rate: Adjust so that the peak of 3-pentanone appears in 4–8 minutes 
after injection. 
Injection method: Cold on-column injection method. 
Assay  The procedure given here should be done as quickly as possible in order to 
avoid humidity.  
 
   Weigh accurately 2 g of Dimethyl Dicarbonate, add 100 mL of acetone 
(dehydrated), and mix. To this solution, add exactly 20 mL of dibutylamine−toluene 
TS (1 mol/L), stir, and immediately titrate the excess dibutylamine with 1 mol/L 
hydrochloric acid using an automatic potentiometric titrator. Perform a blank test 
in the same manner, and determine the content of dimethyl dicarbonate by the 
formula: 
Content (%) of dimethyl dicarbonate (CHO) 
= (a − b) × 0.1341
Weight (g) of the sample × 100 
a = volume (mL) of 1 mol/L hydrochloric acid consumed in the blank test. 
b = volume (mL) of 1 mol/L hydrochloric acid consumed in the test. 
Storage Standards  Store in a hermetic container at 20–30C. 
 
 
Reagents, Solutions, and Other Reference Materials 
Acetone (dehydrated)  CH3COCH3  [67-64-1]  A colorless, clear liquid. 
Content  Not less than 99.5% of acetone (CH3COCH3 ). 
Specific gravity   d2020: 0.788–0.792. 
Water  Not more than 0.001%. 
Assay  Analyze 0.2-μL portions of acetone by gas chromatography using the 
operating conditions given below. Measure the peak area of each peak to determine 
the percentage of the main peak by the peak area percentage method. 
Operating conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.53 mm internal diameter and 30 m length) 
coated with a 5.0 μm thick layer of dimethylpolysiloxane for gas 
chromatography. 
Column temperature: Maintain the temperature at 40C for 5 minutes, 
raise at 5C/minute to 90C, and maintain the temperature at 90C for 
2 minutes. 
Injection port temperature: 150°C. 
Detector temperature: 150C. 
Carrier gas: Helium. 
Flow rate: 5 mL/min. 
  
 
tert-Butyl Methyl Ether  C5H12O  [1634-04-4]  A colorless liquid. 
Content  Not less than 99.5% of tert-butyl methyl ether (C5H12O). 
Specific gravity  d2020: 0.738–0.744. 
Water  Not more than 0.08%. 
Assay  Analyze 0.2-μL portions of tert-butyl methyl ether by gas 
chromatography using the operating conditions given below. Measure the peak 
area of each peak to determine the percentage of the main peak by the peak area 
percentage method. 
Operating conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.53 mm internal diameter and 15 m length) 
coated with a 5.0 μm thick layer of a mixture of 5% phenyl/95% 
methylpolysiloxane for gas chromatography. 
Column temperature: Maintain the temperature at 40C for 10 minutes, 
raise at 20C/minute to 260C, and maintain the temperature at 260C 
for 4 minutes. 
Injection port temperature: 200°C. 
Detector temperature: 260C. 
Carrier gas: Helium or Nitrogen. 
Flow rate: A constant rate of about 4 mL/min. 
Injection method: Split. 
Split ratio: 1 : 50. 
 
Dibutylamine  C8H19N  [111-92-2]  A colorless, clear liquid. 
Content  Not less than 99.0% of dibutylamine (C8H19N). 
Specific gravity   d2020: 0.756–0.764. 
Water  Not more than 0.3%. 
Assay  Analyze 0.2-μL portions of dibutylamine by gas chromatography using 
the operating conditions given below. Measure the peak area of each peak to 
determine the percentage of the main peak by the peak area percentage method. 
Operating conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.32 mm internal diameter and 25 m length) 
coated with a 1.2 μm thick layer of polyethylene glycol for gas 
chromatography. 
Column temperature: Maintain the temperature at 60C for 2 minutes, 
raise at 5C/minute to 100C, and maintain the temperature at 100C  
 
for 20 minutes. 
Injection port temperature: A constant temperature of 150170°C. 
Detector temperature: 200C. 
Carrier gas: Nitrogen. 
Flow rate: Adjust the retention time of dibutylamine to about 20 minutes. 
Injection method: Split. 
Split ratio: 1 : 80. 
 
Dibutylamine–Toluene TS (1 mol/L)  Dissolve 129.3 g of dibutylamine in toluene 
to make 1000 mL. Prepare before use. 
 
Dimethyl Carbonate  C3H6O3  [616-38-6]  A colorless to slightly light yellow 
liquid. 
Content  Not less than 98.0% of dimethyl carbonate (C3H6O3). 
Refractive index  nD20: 1.365–1.372. 
Water  Not more than 0.2%. 
Assay  Analyze 0.2-μL portions of dimethyl carbonate by gas chromatography 
using the operating conditions given below. Measure the peak area of each peak to 
determine the percentage of the main peak by the peak area percentage method. 
Operating conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.32 mm internal diameter and 15 m length) 
coated with a 5.0 μm thick layer of dimethylpolysiloxane for gas 
chromatography. 
Column temperature: Maintain the temperature at 50C for 10 minutes, 
raise at 20C/minute to 250C, and maintain the temperature at 250C 
for 5 minutes. 
Injection port temperature: 200°C. 
Detector temperature: 260C. 
Carrier gas: Helium. 
Flow rate: A constant rate of about 1.5 mL/min. 
Injection method: Split. 
Split ratio: 1 : 200. 
 
Nitric Acid (for trace metal determination)  HNO3  [K8541, for trace metal 
determination] [7697-37-2]  Use a reagent with a nitric acid concentration of 69–
70%, unless otherwise specified.  
 
 
3-Pentanone  C5H10O  [96-22-0]  A colorless to light yellow liquid. 
Content  Not less than 98.0% of 3-pentanone (C5H10O). 
Refractive index  nD20: 1.390 –1.396. 
Water  Not more than 0.2%. 
Assay  Analyze 0.2-μL portions of 3-pentanone by gas chromatography using the 
operating conditions given below. Measure the peak area of each peak to determine 
the percentage of the main peak by the peak area percentage method. 
Operating conditions 
Detector: Flame ionization detector. 
Column: A fused silica tube (0.32 mm internal diameter and 15 m length) 
coated with a 5.0 μm thick layer of a mixture of 5% phenyl/95% 
methylpolysiloxane for gas chromatography. 
Column temperature: Maintain the temperature at 70C for 10 minutes, 
raise at 20C/minute to 250C, and maintain the temperature at 250C 
for 6 minutes. 
Injection port temperature: 250°C. 
Detector temperature: 260C. 
Carrier gas: Helium. 
Flow rate: A constant rate of about 1.5 mL/min. 
Injection method: Split. 
Split ratio: 1 : 300. 
 
 
Infrared Reference Spectrum  
 
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