北检（北京）检测技术研究院

This test method is used to determine the percent actives in each type of the disinfectant quaternary ammonium salts and also in the disinfectant products. Quaternary ammonium compounds being the active ingredients in disinfectant-type products require accurate determination to assess the cost and antimicrobial performance of such products.

1.1 This test method covers a potentiometric titration procedure for determining active matter in disinfectant quaternary ammonium salts. This test method is intended for the analysis of quaternary ammonium salts used as disinfectants and only applies to the following commonly used quaternary ammonium salts: n-alkyldimethylbenzylammonium chloride (see Fig. 1) cetyltrimethylammonium chloride and a blend of n-octyldecyl dimethylammonium chloride di-n-octyl dimethylammonium chloride and di-n-decyldimethyl ammonium chloride (see Fig. 2). Also this test method can be applied to the analysis of disinfectant type products where the formula ingredients are known and the quaternary ammonium salt is one of the above. Interferences such as amines oxides and betaines present in disinfectant formulations were not tested.

1.2 This disinfectant quaternary ammonium salt conforms to the structures in Fig. 1 and Fig. 2.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns if any associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary information see Section 8.