| 摘要 |
The invention relates to an aqueous disinfecting composition, of given pH, containing at least one disinfecting agent, one halochromic compound which changes colour at a pH below the pH of the composition, and the acid form of which is colourless, and one "pH-regulating" reagent capable of causing a decrease in the pH of the composition to a value below the pH for the colour change of the halochromic compound. The halochromic compound and the pH-regulating reagent are selected, and are present in the composition in concentrations, such that, when the composition is applied as a thin layer to a substrate in the open air, the halochromic compound substantially entirely loses the colour thereof in a predetermined period of time in such a way as to attest to a satisfactory disinfecting action of the disinfecting agent. |
