Effects of Persulfate Reagent Stability on a Total Organic Carbon Analyzer Instrument Blank Values


Consideration of detection limits is an important tool for low-level Total Organic Carbon (TOC) measurements. An instrument detection limit not only establishes how low a sample concentration can be quantified, it is also an indirect indicator of the ease at which low level concentrations can be measured with good accuracy and precision. Detection limits are determined by the ratio of sample TOC response to TOC background for a given instrument. Instrument background is often referred to as the instrument blank. The amount and stability of the blank has a major impact on the instrument detection limits and reproducibility. In general this analytical parameter is only important for the low level measurement of TOC such as surface, drinking, high-purity water and Water For Injection (WFI). 1 This paper will examine the reagent stability of two oxidants commonly used for Ultraviolet Persulfate (UV/ Persulfate) analysis.