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AWWA QTC98268
- Are You Reporting Valid TOC Numbers? The Importance of Analytical Methods and NOM Characteristics in TOC Reporting
- Conference Proceeding by American Water Works Association, 01/01/1998
- Publisher: AWWA
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This paper describes how a series of pure compounds of varying molecular weights (humic acids, amino acids, and proteins) was analyzed using the two instrument types. Additionally, numerous natural water samples with distinctly different Natural Organic Material (NOM) characteristics were analyzed for Total Organic Carbon (TOC), turbidity, and NOM fractionation. An Apparent Molecular Weight (AMW) fractionation device was used to separate the natural water samples into molecular weight ranges, thus allowing the TOC analysis within a particular molecular weight range. Comparison of the two oxidation methods showed that larger molecules, such as humic substances, resulted in higher TOC values for the combustion method. The UV/Persulfate instrument produced results that were consistently lower than those of the combustion method. Tests using proteins showed similar results, with up to a 20% difference in the reported value. Easily oxidized compounds showed little difference in the reported value using either instrument.