摘要 |
A method of detecting the initial concentration of a water-treatment chemical present in a diluted aqueous system, by (1) incorporating into the aqueous system, a mixture including a known amount of the active ingredient and a known amount of an ultra-violet sensitive compound having the formula (I): <IMAGE> I wherein halogen is chlorine or bromine; X is CN, SO3M, SO2NHC2H5,SO2NH(CH2)3N(CH3)2, <IMAGE> and a and b, independently are 0 or 1; M is hydrogen or an alkaline metal ion; and (2) detecting the concentration of the compound of formula I, by exposing to ultra-violet light a sample of the aqueous system so treated. |