Dimethyl dicarbonate (CAS Reg. No. 4525-33-1) may be safely used in food in accordance with the following prescribed conditions:
principles of method
Dimethyl dicarbonate (DMDC) is mixed with excess diisobutylamine with which it reacts quantitatively. The excess amine is backtitrated with acid.
apparatus
250-milliliter (mL) Beaker
100-mL Graduate cylinder
25-mL Pipette
10-mL Burette (automatic, e.g., Metrohm burette)
Stirrer
Device for potentiometric titration
Reference electrode
Glass electrode
reagents
Acetone, analytical-grade
Solution of 1 N diisobutylamine in chlorobenzene, distilled
1 N Acetic Acid
procedure
Accurately weigh in about 2 grams of the sample (W) and dissolve in 100 mL acetone. Add accurately 25 mL of the 1 N diisobutylamine solution by pipette and allow to stand for 5 minutes. Subsequently, titrate the reaction mixture potentiometrically with 1 N hydrochloric acid (consumption=a mL) while stirring. For determining the blank consumption, carry out the analysis without a sample (consumption=b mL).
calculation
Note: For adding the diisobutylamine solution, always use the same pipette and wait for a further three drops to fall when the flow has stopped.
21 C.F.R. §172.133