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Elemental analyzer iso TOC cube for EA-IRMS
iso TOC cube®
Elemental analyzer inlet for EA-IRMS
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Fully integrated TOC/TNb isotope ratio analysis

Stable isotope analysis helps to understand the processes that control the carbon and nitrogen cycling in aquatic systems. The quantitative and isotopic analysis of dissolved matter (e.g. dissolved total organic carbon, total bound nitrogen, etc.) is of particular importance since this pool is a prime conduit in the cycling of nitrogen and carbon. The iso TOC cube elemental analyzer inlet presents a new high-temperature combustion method for the quantitative and isotopic analysis of dissolved total organic carbon (TOC) and dissolved total bound nitrogen (TNb). It is the only instrument capable of performing these analyses, making it an indispensable tool for ecologists, limnologists, and oceanographers.

Highlights of the iso TOC cube

Direct δ13C isotope analysis of TOC in aqueous samples

with the possibility of column preconcentration for low TOC samples

Direct δ15N isotope analysis of TNb in aqueous samples

with the only commercially available instrument capable of this kind of analysis

High sample throughput

thanks to a direct analysis method which does not require sample preparation

High system uptime

thanks to low-maintenance design


Direct δ13C isotope analysis of TOC in aqueous samples

The iso TOC cube is a combustion analyzer with greater analytical robustness and less maintenance than analyzers working with wet-chemical or UV oxidation methods. Even when analyzing refractory organic substances such as humic acids or lignin, which are traditionally difficult to combust, you can expect reliable, matrix-independent measurement results thanks to the complete conversion of all compounds at these high combustion temperatures. Thus, the iso TOC cube enables dissolved carbon and nitrogen isotope ratio analysis with highest precision and accuracy in all types of liquids, from drinking water or industrial wastewater up to soil leachates, suspensions, brines, or marine samples. For low TOC samples the iso TOC can be configured with an optional column, which preconcentrates TOC.

The one and only analyzer for direct δ15N isotope analysis of TNb in aqueous samples

The iso TOC cube elemental analyzer for EA-IRMS is the only commercially available instrument capable of simultaneous isotope ratio analysis of dissolved total organic carbon (TOC) and dissolved total bound nitrogen (TNb) in aqueous samples. For the δ15N analysis of TNb, the iso TOC cube uses our unique Low Concentration Module (LCM) and an integrated membrane degasser for removing dissolved N2, increasing sample detection levels. The LCM uses cryogen-free, thermoelectric cooling combined with our Advanced Purge and Trap (APT) separation technology to achieve TNb detection levels of 25 ppm.

High sample throughput thanks to direct analysis method

By performing direct analysis on the sample, the need for laborious pre-preparation of samples is removed. The direct determination of dissolved carbon and nitrogen out of the liquid phase ensures complete quantitative conversion of all compounds, so that offline sample preparation through freeze drying can be omitted. Designed for unattended 24/7 analysis, iso TOC cube offers highest sample throughput.

High system uptime thanks to low-maintenance design

The iso TOC cube features a 32 position autosampler, which is reloadable at any time. Whenever maintenance is necessary, our user-friendly clamp connections ensure a tool-free experience, while the slide-out furnace guarantees easy accessibility and a comfortable working posture.

Future-proof thanks to 10 years warranty

Thanks to the outstanding robustness and longevity of our iso TOC cube, we grant a 10-year warranty on the high-temperature combustion furnace. With our long-term oriented dedication to technical support, we provide spare parts for a minimum of 10 years. This results in outstanding low total cost of ownership, giving you confidence in return of investment.

Product details

The iso TOC cube is optimized for the analysis of: 

  • δ13

  • δ15N* 

of Total Organic Carbon (TOC), Total Inorganic Carbon (TIC), and Total Bound Nitrogen (TNb)* 

* optionally available

Maximum sample weight

Volume injections up to 3 ml for optimal detection.

Element concentration range 

Large detection range 
From 5 ppm to 60,000 ppm dissolved carbon, 25 ppm to 60,000 ppm for dissolved nitrogen*.


Elemental performance (external precision, 1σ): 
C: < 2 % relative 
N*: < 2 % relative 

Isotope ratio performance (external precision, 1σ): 
δ13C: 0.1 ‰ 
δ15N*: 0.2 ‰ 

Analysis time 

~ 5 min in C mode
~ 15-20 min in CN mode*

Depending on sample type, analysis mode, and configuration.

* optionally available

High-temperature combustion unit 
Quantitative sample digestion in the presence of oxygen at 950 °C - with a 10-year furnace warranty. Optional preconcentration column for CO2 and N2 with the low concentration module.


  • Carbon dioxide specific high sensitivity infrared detector (both stand-alone and IRMS mode)
  • Nitrogen monoxide specific high sensitivity infrared detector (only stand-alone mode)*

Sample introduction 

Sample introduction via freely adjustable syringe injection with bubble elimination feature and integrated liquid autosampler with 32 or 50* positions, reloadable during analysis. With automatic acidification and sparging.

Maximum furnace temperature 

1,200 °C (standard operating temperature: 950 °C)

Instrument control 

Windows® based ionOS® softwarewith LIMS integration and auto sleep and wake-up function for automated and unattended overnight operation.

Required gases 

Helium and oxygen


Module 1:
48 x 63 x 82 cm (W x D x H, including sampling turret)

Module 2*:
27 x 62 x 53 cm (W x D x H)

* optionally available

Electronic balance:

Balance and elemental analyzer form a system. We offer analytical balances from the leading manufacturers with our instruments. Please contact us for further information.

Low Concentration Module (LCM):

Optional device for the pre-concentration of N2 and CO2 after combustion. The LCM provides cryogen-free, thermoelectric cooling to the Advanced Purge and Trap (APT) separation column, allowing sub-ambient temperatures leading to excellent chromatography.


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