TOC Analyzer explained

TOC Analyzer explained

There are a quite a few analyzers in the market today. Which analyzer should you use and what can they measure! In this article you’re going to understand the innerworkings of TOC (and TNb) analyzers as well as user cases, the industry and a brief overview of a useful feature of the TEIS software it comes with.

What are the different types of TOC analyzer?

First things first, what does TOC analyzer actually mean? TOC stands for Total Organic Carbon analyzer. It’s the amount of carbon found in an organic compound. This can either be a gas, liquid or solid.

There are different types of Carbon. All the carbon types are listed below:

TC Total Carbon
TOC Total Organic Carbon
TIC Total Inorganic Carbon
NPOC Non-Purgeable Organic Carbon
POC Purgeable Organic Carbon
VOC Volatile Organic Carbon
DOC Dissolved Organic Carbon


A reason for measuring TOC is because high concentrations have undesirable effect to plants and animals, high TOC levels stimulate bacterial growth which produces toxic substances

As you can see, there are a multiple reasons to analyze the TOC value. Each company or government has their own reasons to do so.


Which industries use the TOC analyzer?

A lot of different industries can use a like the Xpert TOC/TNb. the typical customers are: Environmental labs, surveyors, refineries, (petro) Chemical labs, Research Institutes (pharmacy/environmental), Governmental bodies and standardization bodies. All of these industries have a connection with the following applications:

  • Municipal water
  • Waste water
  • Process water
  • Industrial water
  • Ground water
  • Surface water
  • Sea water and Brines*

*Brines is an auxiliary agent in water softening and water purifications systems involving ion exchange technology.

Basically if you have a connection with a water supply and/or need to disperse waste water, you are most likely going to need an toc analyzer.

The 3 types of TOC analyzer methods

There are three methos for analyzing total organic carbon:

  • High Temperature Catalytic Oxidation
  • High Temperature Combustion
  • UV-Persulfate Oxidation

The Trace Elemental instruments Xpert TOC/TNb uses the High Temperature Catalytic Oxidation method.

High Temperature Catalytic Oxidation

This method combusts a sample at 680 °C utilizing a platinum catalyst in an oxygen rich atmosphere.  Using a Non-Dispersive Infrared detector (NDIR) it detects the carbon dioxide  in the sample. A NDIR is a spectroscopic senor that regularly is used as a gas detector.


The software

The software feature bracketing is often used to monitor the stability of the system or when high confidence in the results is needed. This is done with the use of analyzing calibration standards. The analysis of these standards happens just before and/or after a set of samples. If a deviation of the standards has been concluded, than that can be an indication that the system needs to be re-calibrated or that a (temporary) external factor(s) have influenced the result.  A bracket can be created with 2 scopes. Each scope can have a start, end or both. A batch size scope to all batch size and/or remainder of a batch size. The image shows the process when a bracket is applied.

TEIS - Bracketing

Underneath the bottle compartment are scales. By weighing the bottles and its content the software can determine if the samples set to analyze can be fully analyzed or for example that at an certain point the waste water bottle needs to be emptied. If that’s the case the, TEIS software notifies you. This way you don’t get unpleasantly surprised. Want to know more about the TEIS software? Read about it in our knowledge base page of TEIS here.



So, now you know how the total organic carbon analyzer works and what fields use them. If there are question that haven’t been answered, please check out the Xpert TOC/TNb for more information. Otherwise you can contact us by filling out the contact form on the website or send an email to