摘要 |
<p>A colorimetric device for indicating carbon dioxide is disclosed, which device contains: a) at least one pH-sensitive indicator dye, b) at least one basic substance selected from the group consisting of quarternary ammonium salts, phosphonium salts and sulphonium salts, and c) at least one member selected from the group consisting of water-insoluble, organic substances of low volatility, which are not susceptible to alkaline hydrolysis and are liquid at room temperature or moderately elevated temperatures.</p> |