Reliability of TOC Results In Ultra-Pure Water Analysis

The intent of this technical note is to discuss current methods of TOC (Total Organic Carbon) analysis, including their advantages and limitations in the analysis of ultrapure water. For purposes of this paper, "ultrapure" water is defined as that water in the 500 ppb (parts-per -billion) range of TOC and lower. The two basic components of any TOC analyzer defining accuracy and precision of analysis are: 1. The Oxidation Reactor, which converts the organic carbon in the water to CO2 gas, usually either by thermal, chemical or ultraviolet radiation. Oxidation efficiency, assuring complete conversion of the organic carbon to CO2, is critical. AND 2. The CO2 Detector, which measures the concentration of the CO2 gas generated in the oxidation chamber. This component is critical for precise analytical results, since it directly correlates to the organic carbon content of the analyzed water.