| 摘要 |
Apparatus for measuring the concentration of a contaminant in a fluid comprises a measuring chamber, a first source of optical radiation of predetermined wavelength which is directed through the chamber, a detector to detect the transmitted radiation and a pump to supply fluid to the measuring chamber. A reference measurement is provided by periodically diverting the supplied fluid through means which either removes a contaminant which is detectable at the wavelength used, or converts an undetectable contaminant to a detectable compound. A system for detecting contaminants in water has modulated light sources at 253.7 nm (for detecting ammonia, organic and suspended matter) and at 206 nm (for detecting nitrate ions). Nitrate ions and organic matter can be removed using resin ion-exchange columns, whereas ammonia is made detectable at 253.7 nm by conversion to monochloramine on addition of chlorine. |
