Introduction: TOC Analysis in Process Control
Total organic carbon (TOC) analysis provides valuable process data in industrial water treatment and drinking water treatment by efficiently measuring sample impurities through simple, comprehensive detection of organic contamination. Accurate assessment and quantification of low TOC concentrations is critical for process control, product quality, and asset protection. Organic contamination, such as volatile organic compounds (VOCs), can cause interference in production processes, contaminate finished products, cause non-conformity throughout a production lot as well as degradation of equipment.
The Challenge of Volatile Organic Compounds (VOCs) Detection
Compounds that are volatile or semi-volatile have uses in cleaning and cooling applications, while others emerge from source water or breakdown products. The ability to detect these volatile and semi-volatile compounds can be achieved using TOC analysis, and is key to identifying process upsets, leaks, or process inefficiencies in municipal and industrial water treatment. Since volatile organic compounds (VOCs) are lost through sparging, they can be difficult to detect depending on the analytical tool selected. Some tools require sparging with a carrier gas, specialized method development, or the purchase of additional accessories to support VOC measurements. These limitations may lead to delayed or improper decision-making due to inaccurate data.
Comparative Analysis: TOC Oxidation Methods
In a recent study comparing the recovery of volatile compounds with different total organic carbon (TOC) analyzers, the following three TOC oxidation methods were used:
- High temperature catalytic combustion
- Two staged advanced oxidation
- UV persulfate oxidation with membrane detection (used in Sievers M-Series TOC Analyzers)
All the listed methods were able to detect VOCs when functioning in the proper mode; however, Sievers M-Series are the only analyzers able to detect volatile organics in the standard mode of operation without the use of a carrier gas. This is beneficial because sparging with a carrier gas can result in the loss of volatile and semi-volatile organic compounds. Also, using a carrier gas for an NDIR detector requires a gas-liquid separator to remove any moisture which will negatively affect its operation. Sievers M-Series Analyzers remove these risks by measuring CO2 in the liquid phase (rather than the gas) via membrane conductometric detection.
Identifying leaks or process inefficiencies quickly and at low concentrations can save time and money by protecting equipment and finished products. Early detection of process upsets allows users to make informed decisions, using data to mitigate risks and control processes. Sievers M-Series TOC Analyzers meet this requirement with the lowest limit of detection (LOD) and limit of quantification (LOQ) alongside the most accurate low-level analysis of volatile compounds. Combining analytical accuracy, overall ease of use, and the lack of requirement to purchase optional accessories makes Sievers M-Series TOC Analyzers the ideal solution for detection of volatile organic compounds.
Learn more about this study here.