TOC & Water Analysis

The content of total organic carbon (TOC) in water and solid samples - as a sum parameter for organic pollution - is one of the most important screening parameters in environmental analysis. The challenge to measure TOC with highest precision and accuracy for a multitude of applications in combination with the opportunity to analyze other elements, like nitrogen, simultaneously has been solved by the flexible analyzers of Elementar.

TOC analysis in water - anything is possible

From ultra-pure water to waste water, any liquid sample can be analyzed by a TOC analyzer of Elementar:

The acquray® TOC is a newly developed, highly sensitive, wet-chemical analyzer for the determination of organically and inorganically bound carbon in aqueous samples. The irradiation with UV light at two wavelengths (254 nm and 185 nm) in combination with chemical oxidation (sodium persulfate) and heating is very powerful and guarantees a complete digestion of even most stable carbon compounds. The high injection volumes (up to 40 ml) make the acquray TOC the perfect solution for the determination of low TOC concentrations in ultra-pure water. The option to measure also total phosphorus and total nitrogen simultaneously in one sample is unique worldwide.

Elementar's high temperature combustion method realized in the vario TOC series is optimized to deal with compounds hard to oxidize, such as humic acids or other rather persistent compounds. Therefore, the TOC content can be determined fully automatically in such different samples as ultrapure water, waste water, waste and soils with analyzers of the vario TOC series. The instruments of the vario TOC series have an optimized tubing and connection system for a reliable, trouble-free handling of liquid samples containing particles. With the unique matrix separation concept, which protects the catalyst, concentrated salt solutions can be analyzed even in larger injection volumes. The choice between CLD, EC, or IR detection for the determination of TNb compliant with EN 12260 covers all user needs.

TOC analysis in solids - Methodological flexibility in combination with liquid analyzers

Particularly the automatic determination of TOC in solids still represents a challenge for many combination devices which was completely solved by Elementar. The vario TOC series allows measurement of solid and liquid samples compliant with relevant standards like ISO 8245, EN 1484 (liquids) or EN 15936 and ISO 10694 (waste and soils) with a single instrument - retrofitting is done within minutes.

Another important topic is the method to distinguish between Total Organic Carbon (TOC400) at 400 °C, Residual Oxidizable Carbon (ROC) at 600 °C and Total Inorganic Carbon (TIC900) at 900 °C by using a temperature ramp compliant with DIN 19539 (released in 2016). The differentiation of carbon fractions delivers useful information for the validation of soils or solid waste. For example, the amount of elemental carbon is an important parameter, since this form of carbon is not bioavailable and can be differentiated from the bioactive TOC by temperature. The technique has been realized in the soli TOC®  cube, fully automated for unattended operation and with flexible method settings, which offers the opportunity to use it for the solution of complex research questions related to carbon fractions. With the optional solid sample combustion unit of the acquray series, it is also possible to determine different carbon fractions in solids using the so called temperature ramp method. The soli TOC cube and the acquray operate in full compliance with all relevant standards for determination of TOC in solids, not only the temperature ramp defined in DIN 19539, but also the TOC determination at constant temperature compliant to EN 15936 or ISO 10694 is possible.