Calibration gases and auxiliary gases for analytical purpose (F)

Vadilal has more then 15 year’s experience in the production of Calibration gas mixtures. Production first started at Por, Baroda unit in 1998. Today, Vadilal manufactures practically all types of mixtures, to the extent allowed by the individual components’ chemical reactions or physical character.

Gas mixture are used within main areas:

• Calibration gases and auxiliary gases for analytical purposes.
• Gas mixtures for use in industrial processes.

Calibration gases and auxiliary gases for analytical purpose

As the majority of methods of analysis are not absolute, but only produce a relative response, it is necessary to calibrate with a standard which has known composition and concentration, in order to accurately determine the content of the sample analysed.

Calibration gases are therefore required to be accurate, stable and homogeneous. The concentration of each component must be specified together with a guarantee of accuracy of the certified value over a certain period of time.

These gas mixtures are produced from pure raw material, with a known content of impurities. A wide variety of pure gases and liquids are available to cover a comprehensive product range.

Requirements for auxiliary gases, such as carrier gases and detector gases for gas chromatography, are often not as strict as those for calibration gases.

Gas mixture used in industral processes

These are mixtures used in a process, based on the components’ chemical or physical properties; e.g. gas mixtures for lasers and rare gas mixtures for production of light bulbs.

Production of Calibration gas mixtures

The production of gas mixture follows the flow chart below. A more simple flow chart is followed for basic mixed gases understanding.

The selection of production method depends on which components are to be included in the mixture and the accuracy required on the certificate.

The correct choice of cylinder material and valve, together with special internal treatment of the cylinder, are essential to achieve stable mixtures.

Filling of gas components follows several different methods, either separate or combined.

The gravimetric, method, where each components is weighed separately, is the most accurate and is used for production of Vadilal’ primary standards. Gravimetric mixtures are normally certified according to the gravimetric production data, and analysed to verify the values. Mixtures produced according to the mano - metric method (partial pressure of each components is measured) or volumentric method (volume of each components is measured) are certified on the basis of analysis data.

All stages of the production process, from receipt of the order to dispatch of the product, are subject to strict quality assurance requirements. The production of special gas components is certified pursuant to ISO 9001:2008.