Versatile Calibration of Trace Gas Analysers

Calibration of trace gas analysers is key for reliable quantification but it is also challenging in many ways, ranging from a well-defined production of stable trace concentrations to the choice of the right materials to minimise surface effects.

Ionicon Analytik (Austria) as a specialist manufacturer of real-time gas analysers and has many years of experience in trace gases analysis and calibration. Ionicon’s successful Gas Calibration Units (GCU) series relies on down-mixing of gaseous calibration standards. These reliable and simple-to-use instruments depend on the availability of gaseous standards for the compounds of interest. To provide more flexibility in the choice of the compounds to calibrate Ionicon has released a new series of calibration products.

The Ionicon Liquid Calibration Unit (LCU) evaporates aqueous calibration standards into a gas stream, resulting in a gas flow containing compounds at defined trace concentrations. The preparation of an aqueous standard mixture is simple and can be done immediately for a large variety of compounds. A very low solubility of a compound in water is already sufficient to achieve the desired trace concentrations.

To produce gas concentrations of organic and inorganic compounds, the Ionicon LCU evaporates a defined flow of an aqueous standard into a clean gas stream of 1000 ml/min. A special flow controller allows precise control of the liquid flow between 1 and 50 µl/min. Its internal volumes have been reduced to a minimum to allow fast rinsing and quick change to another standard. The concentrations that can be produced range from ‰ down to ppt. The highly efficient evaporation in the LCU is achieved by nebulisation of the liquid. The resulting micro-droplets evaporate in a heated evaporation chamber. This has been shown to work both for volatile as well as semi-volatile compounds. The LCU has successfully been tested with a growing variety of compounds, including ketones, aldehydes, alcohols, amines, terpenes, organic acids, and esters. Moreover, an additional gas flow controller allows the admixing of gas calibration standards, adding the ease of use of gaseous standards to the flexibility aqueous standards offer.

The LCU is a cost efficient and highly versatile calibration device for trace gas analysers that can be implemented in many fields of research, such as food and flavour, biotechnology, breath-gas analysis, environmental research, and petrochemical analysis.