Understanding rouging: Rouge performance effects and rouge cleaning in an ANATEL TOC analyzer


Corrosion of stainless steel surfaces in pharmaceutical water systems results in the formation of colored deposits known as rouge. Rouging is a common problem in Water for Injection (WFI) systems where high temperatures and dissolved gases accelerate corrosion and formation of iron oxides. Corrosion products, such as iron oxide, can break away from stainless steel surfaces and flow through the entire water system to deposit on surfaces farther downstream. When rouge adheres to the interior walls of quartz glass oxidation cells in online total organic carbon (TOC) analyzers, the accuracy of TOC measurements can be affected. TOC analyzers that are rouge-resistant or can be cleaned periodically to remove rouge deposits while remaining online have a significant competitive advantage. This white paper investigates the sources of rouge formation in a Hach Ultra ANATEL TOC instrument, and demonstrates that an effective cleaning solution has been developed that can be employed as part of routine preventive maintenance.