The use of chlorophenol red for the selective determination of chlorine dioxide in drinking water.
In recent years, the use of chlorine dioxide as an alternative disinfectant for drinking water has become increasingly attractive. As a result, an accurate method for the determination of mg l(-1) concentrations of chlorine dioxide is needed. Improvements to chlorophenol red (CPR) spectrophotometry result in a selective method for ClO(2) with few interferences. CPR selectively reacts with 0.1-1.9 mg l(-1) ClO(2) at pH 7, yielding a linear response (0.9994) with a limit of detection of 0.12 mg l(-1) ClO(2). Several species, ClO(2)(-), ClO(3)(-), NH(2)Cl, and free available chlorine (FAC), were studied as potential interferents using this method. There was found to be less than 2% interference due to 1.38 mg l(-1) ClO(2)(-), 9.87 mg l(-1) ClO(3)(-1), and 5.31 mg l(-1) NH(2)Cl. The interference from up to 1.19 mg l(-1) FAC was 3.7% and could be further reduced by the addition of oxalic acid, sodium cyclamate or thioacetamide.
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Sullivan
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Gordon
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