REAGENT SOLUTION TO MEASURE CONCENTRATION OF DISINFECTANT

The invention relates to a reagent solution comprising raw materials, wherein the raw materials comprise:(a) a sulfite selected from sodium sulfite, sodium bisulfite and combinations thereof;(b) a pH indicator/absorbance species selected from phenolphthalein, O-cresolphthalein, p-naphtholbenzene, ethyl-bis(2,4-dimethylphenyl)acetate and thymolphthalein;(c) an acid selected from hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, organic carboxylic acids and combinations thereof;(d) isopropanol; and(e) water;wherein the reagent solution is configured to be mixed to form a ready-to-use solution that reacts with ortho-phthalaldehyde concentration in a liquid sample.