What should be avoided when using quaternary ammonium salts for disinfection?

When using quaternary ammonium salts, also known as quats, for disinfection, it is essential to avoid combining them with soap. This is because soaps can interfere with the activity of quaternary ammonium compounds. Soaps, which are anionic surfactants, can bind to the quats and either reduce their efficacy as disinfectants or completely inactivate them. For effective disinfection, quats need to maintain their cationic charge to interact properly with negatively charged microbial cell membranes.

In contrast, alcohol, water, and hydrogen peroxide can have different interactions with quats. Alcohol can be used to enhance the disinfectant properties of certain products without inactivating quats. Water is often used for dilution and does not hinder the action of quats, while hydrogen peroxide can serve as a complementary disinfectant but does not negate the action of quats when used appropriately. Therefore, soaps should be avoided to ensure the maximum antiseptic effect of quaternary ammonium salts.