New Spectrophotometric Method For The Determination Of Trace Residual Chlorine In Drinking Water And Environmental Water Samples.

Author(s): Akheel Ahmed Syed, Rangaiah Sunitha

An improved method using N-1-Napthylethylenediamine dihydrochloride(NEDA) as a chromogenic reagent for determination of residual chlorine is proposed. The method is based on the reduction of chlorine by an electrophilic coupling reagent, 3-methyl-2-benzothiazoline hydrazono hydrochloride hydrate(MBTH) and subsequent coupling with NEDA. The blue color formed in the reaction showed maximum absorbance at 610nm and obeyed Beer’s law over the range 0.3-4.2ppm. The molar absorptivity and Sandell’s sensitivity values were 3.14×103 L mol- 1cm-1 and 0.102μg cm-2 respectively. The proposed methods were successfully applied in determination of residual chlorine in drinking water and environmental water samples. The performances of proposed methods were evaluated in terms of student t-test and variance ratio F-test which indicated the significance of proposed methods over the reference spectrophotometric method.

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