AWWA WQTC55173

In recent years, an increasing number of regulations and methodologies are utilizing Total Organic Carbon (TOC) analysis for the measurement of microbial contamination and/or disinfection byproducts (DBP) precursors. This paper highlights some analytical differences and similarities between the two widely used TOC oxidation techniques: persulfate, and high temperature combustion (HTC). Previous studies have come to different and sometimes contradictory conclusions on this subject. However these studies either compared instruments with significantly different flow paths or TOC systems from different eras. Unlike previous studies, this paper compares two modern TOC analyzers with nearly identical flow paths for sample recovery, detection limits, and analysis of particulates. On average, both persulfate and HTC oxidation yielded good recoveries for hard to oxidize compounds and real world potable water samples. In general, persulfate yielded more precise results because of its lower background response relative to sample response. Whereas, HTC gave slightly higher results, roughly 2% to 3% on average, for surface water samples. Includes 19 references, tables, figures.