Third Commission Directive of 27 September 1983 on the approximation of the laws of the Member States relating to methods of analysis necessary for checking the composition of cosmetic products (83/514/EEC) (c. 514)

ANNEX U.K. DETERMINATION OF DICHLOROMETHANE AND 1,1,1-TRICHLOROETHANE

IDENTIFICATION AND DETERMINATION OF MERCAPTOACETIC ACID IN HAIR-WAVING, HAIR-STRAIGHTENING AND DEPILATORY PRODUCTS U.K.

5. DETERMINATION (see NB) U.K.

5.2. Gas chromatograyhy U.K.

5.2.5. Methylation U.K.

The methylation is carried out either by in situ preparation (5.2.5.1) or with previously prepared diazomethane solution (5.2.5.2).

5.2.5.1. Methylation in situ U.K.

Into the methylation apparatus (5.2.3.2) containing 1 ml of ether (5.2.2.11) introduce 50 μl of solution ‘S’ and methylate by the method (5.2.3.2) with about 300 mg of l-methyl-3 nitro-1-nitrosoguanidine (5.2.2.8). After 15 minutes (the ether solution should be yellow to indicate excess diazomethane) transfer the sample solution to a 2 ml bottle having an airtight stopper. Place in the refrigerator overnight. Methylate two samples simultaneously.

5.2.5.2. Methylation with the previously prepared diazomethane solution U.K.

Introduce, into a 5 ml stoppered flask, 1 ml of diazomethane solution (5.2.2.12) then 50 μl of solution ‘S’. Leave in the refrigerator overnight.