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ASCORBIC ACID TREATMENT TO REDUCE RESIDUAL HALOGEN-BASED OXIDANTS PRIOR TO THE DETERMINATION OF HALOGENATED DISINFECTION BYPRODUCTS IN POTABLE WATER
Citation:
Urbansky*, E T. ASCORBIC ACID TREATMENT TO REDUCE RESIDUAL HALOGEN-BASED OXIDANTS PRIOR TO THE DETERMINATION OF HALOGENATED DISINFECTION BYPRODUCTS IN POTABLE WATER. JOURNAL OF ENVIRONMENTAL MONITORING. Royal Society of Chemistry, Cambridge, Uk, 1(5):471-476, (1999).
Description:
Treatment of potable water samples with ascorbic acid has been investigated as a means for reducing residual halogen-based oxidants (disinfectants)i.e., HOCl, Cl2, Brw and BrCl, prior to determination of EPA Method 551.1A and 551.1B analytes. These disinfection byproducts include certain haloalkanes, haloalkenes, haloethanenitriles, haloaldehydes, haloketones and trichloronitromethane. When used as a dehalogenating agent immediately before analysis, only one analyte, 2,2,2-trichloroethanediol, is significantly decomposed. Ascorbic acid is superior to thiosulfate and sulfite as it does not destroy trichloroethanenitrile, trichloronitromethane or dibromoethanenitrile. Unlike ammonia or amines, it is not nucleophilic and cannot form hemiaminals with carboxaldehydes and ketones. Ascorbic acid treatment can rapidly consume large amounts of active halogen compounds, producing only inorganic halides and dehydroascorbic acid and not additional halogenated organic molecules.