The study of the determination method of residual chlorine in water with bromothymol blue spectrophotometry

It studied a new determination method of residual chlorine with bromothymol blue spectrophotometry. Residual chlorine reacts with bromothymol blue and makes it to fade.In alkale medium,The solution shows blue,λ_(max)=616nm,e=9.17×10~4L/mol·cm.The detection limit(4.6SD) is 0.06mg/L.When it is used to the determination of residual chlorine in water supply,the relative standard deviation is 1.76% and recovery is 97.22%～104.2%.