Abstract
An alternative simultaneous injection-effective mixing analysis system controlled by a personal computer was proposed for the determination of residual chlorine. This system consists of a sequential injection mode (SI), a multi-commutation mode (MC) and a flow injection mode (FI). Chlorine reacts with 4,4'-bis-dimethylaminothiobenzophenon dissolved in Triton X-100, 2-methoxyethanol and formic acid/fomate buffer to form a blue compound (λmax, 640 nm). The calibration graph was linear in the range of 0–1.68 mg L−1 chlorine and the regression coefficient was 0.999. The RSD for 0.56 mg L−1 chlorine (n = 5) was 0.37% and the repeatability was excellent. The sampling rate for one analysis was 41 s. This method is less reagent consuming and the sensitivity is excellent. This method is applicable to the determination of residual chlorine in tap water.
