TOC (TOTAL ORGANIC CARBON) DETERMINATION IN THE ENVIRONMENTAL SECTOR: BEST PRACTICES FOR ACCURATE ANALYSES

21/06/2022

Learn how to determine total organic carbon concentration and the basic steps to perform an accurate analysis with the VELP CN 802 Elemental Analyzer.

TOC (TOTAL ORGANIC CARBON) DETERMINATION IN THE ENVIRONMENTAL SECTOR: BEST PRACTICES FOR ACCURATE ANALYSES

There are numerous international laws, ordinances, and regulations that impose certain environmental conditions necessary to guarantee a certain standard of quality.

In this context, instrumental analysis becomes a useful tool to measure the state of these conditions.

One possible application is the analysis of sewage sludge generated by wastewater treatment plants. In recent years, they have become the subject of increased attention in light of their potential to improve soil properties and provide important supplements of nutrients and trace elements essential for plant growth.

Knowing the parameter of TOC (Total Organic Carbon) is essential to determine the total concentration of organic carbon and then the organic pollution, which impedes the anaerobic digestion process, limiting the nitrogen enrichment of the subsoil.

The VELP CN 802 elemental analyzer is a complete and accurate solution for the determination of nitrogen and carbon content, including total organic carbon (TOC), in the environmental sector.

Sample preparation for TOC determination with the CN 802 elemental analyzer

The measurement of total organic carbon requires the sample is appropriately homogenized and dried directly at 105 °C to remove all traces of moisture.

The sample is then subjected to acidification inside the VELP Silver Foil (code A00000371) and plate for TOC (TA00000378).

By adding a small amount of HCl (Hydrochloric Acid), the inorganic carbon content is converted to CO₂and eliminated, leaving only carbon of organic origin in the sample.

Once the acidification process is complete, the sample can be analyzed in the CN 802 elemental analyzer, automatically achieving reliable, accurate, and repeatable results, thanks to the innovative CNSoft^TM software.

The VELP CN 802 working principle

The elemental analysis starts with a combustion furnace (CF) to burn the sample.

Water is removed by a first physical trap (WT1 - DriStep™), placed after the combustion, and a second chemical one (WT2).

Between the two, the elemental substances passed through a reduction furnace (RF).

VELP exclusive Non-Dispersive Infrared NDIR Detector accurately measures the CO₂ concentration that the unit is able to convert into carbon quantity.

Then, the auto-regenerative CO₂absorbers pass only the elemental nitrogen that is detected by the LoGas™ innovative Thermal Conductivity Detector (TCD) with no requirement for a reference gas.

Maximum productivity, high accuracy and cloud potential

The CN 802 is a robust and flexible combustion analyzer that works in accordance with official reference methods for determining carbon and nitrogen in organic matrices.

The CN 802 is powered by the CNSoft^TM software and produces unsupervised results for:

Total Carbon - TC
Total Organic and Inorganic Carbon (after acidification) - TOC, TIC
Total Nitrogen - TN
C/N Ratio

Thanks to the non-stop performance, the instrument guarantees high productivity in the laboratory.

The connection to the innovative VELP Ermes cloud platform makes it easy to monitor and control the analysis in real-time via PC, smartphone, or tablet, freeing up valuable time for other tasks.

Read the application note and discover the results obtained on sludge samples, with the VELP CN 802.

READ THE APPLICATION NOTE