When measuring for information only, TOC sensors can be excellent tools. When measuring to make critical quality decisions, TOC Analyzers are essential.
Differences Between TOC Analyzers and Sensors
It is critical to select the right TOC measuring device for its intended application. There are many differences between TOC analyzers and TOC sensors, and it is important to understand their consequences. If the intended TOC device use is for regulatory reporting, managing an important process control variable, real-time release, or other critical-to-quality product attributes, instrument accuracy is essential. If the intended use is for general TOC monitoring—not for making critical quality decisions—then other characteristics may be more important than accuracy.
All TOC Sensors are less accurate than TOC Analyzers. Sensors are typically used to monitor a process while Analyzers are more suited to manage a process. Data from Sensors are used for information only, and data from Analyzers are used to make critical quality decisions. TOC Analyzers and Sensors serve important, but different uses and roles in today’s ultrapure water (UPW) applications
TOC Analyzer and Sensor Technologies
TOC Sensors all measure the CO2 directly by conductivity cells (Direct Conductivity, or DC method) and can produce false positive and false negative TOC results. In contrast, TOC Analyzers remove the CO2 by diffusion through a selective membrane into deionized (DI) water and then measure the ionized CO2 by a conductivity cell using the Membrane-Conductometric (MC) method.