Gas measurements in freight containers

Freight container measurements

Cargo containers and wooden packing materials are fumigated to control the spread of pests and micro-organisms. However, fumigant gases are toxic and present a danger to human health even at low concentrations. Additionally, products shipped in containers may release VOCs from the solvents, coatings and glues used in manufacturing processes, and the concentrations of these vapors may be significant in the confined space of the container. Gas measurements are required in order to protect the health of any workers involved in opening these containers.

The video below demonstrates the use of the DX4040 for measuring gases inside cargo containers. Some background facts are explained and the functionality of the DX4040 for this application is presented by means of a demonstration measurement.

As potentially hazardous gases originate from a variety of different sources, the amount of gases that need to be monitored, in order to ensure a safe working environment, is very large. The FTIR (Fourier Transform Infra-Red) measurement principle allows simultaneous measurement of a large amount of inorganic and organic substances, regardless of their molecular weight. The portable Gasmet™ DX4040 Multicomponent FTIR Gas Analyzer records infrared spectra at 10 scans/second and is capable of sub-ppm detection. When used with a laptop computer and the pro version of Calcmet™ software, the DX4040 is capable of analyzing up to 50 components simultaneously with compensation for cross-interference effects.

A standard application has been developed for container measurements. The application consists of a gas library of 50 gases that has been configured to include all of the most important fumigants and other hazardous gases found in containers, along with a number of other commonly found gases for correction of cross-interference effects. A built-in QA/QC routine ensures reliable results and alerts the user of the possibility of unknown gases in the sample.

If the presence of unknown gases in the sample is suspected, these can be identified using the library search function available in the CalcmetTM software. Identification is undertaken by automatically finding matching spectra in the library of hundreds of different reference spectra measured by Gasmet for different compounds. Once the unknown compound has been identified, it can be added to the analysis for quantification. The measured sample spectra are not altered by the analysis and are saved so they can be re-analyzed at a later time if needed.

The Gasmet™ DX4040 is battery powered, backpack sized designed for use in field conditions. The analyzer is portable, so there is no need for separate sampling and the sample can be collected and analyzed directly on site. Quick and easy sampling, coupled with fast, simultaneous analysis of all compounds makes for an exceptionally quick measurement procedure per container. The DX4040 requires no span gas calibrations and uses no consumables for sampling or analysis. Only a short zero calibration with nitrogen is required once per day. This means that containers can be measured quickly and with a negligible cost per measurement.


The Gasmet DX4040 provides a powerful and cost effective solution to the challenge of measuring gases inside cargo containers. The use of FTIR technology enables the simultaneous measurement of an unparalleled amount of gases for a portable device, which leads to improved safety of workers. The DX4040 is also durable, requires no calibration gases (other than N2 for zero measurement) and requires no consumables for sampling. This means that the cost of ownership for this solution is also exceptionally low.  

Advantages in a nutshell:

  • Simultaneous multicomponent analysis of up to 50 compounds
  • Rapid sampling and analysis on site
  • Ability to QUANTIFY knowns and IDENTIFY unknowns
  • Low cost of ownership (only zero calibration with N2 required)
  • FTIR measures both organic and inorganic fumigants
  • Futureproof – New compounds can easily be added to analysis
  • Calcmet software provides a powerful tool for analyzing sample spectra
  • Precise results in demanding field conditions
  • Lightweight, battery powered
  • Cross-interferences automatically compensated
  • Non-destructive analysis