VOC speciation using purge and trap technology

Chromatotec has developed enhanced headspace sampling systems designed to extract representative compounds from the liquid phase. The vaporised sample is preconcentrated using a trap to achieve quantification of VOCs at trace and ultra-trace levels. Then, it is injected automatically and in continuous mode into our auto-GC-FID analysers.

A headspace-chromaFID has been deployed in refineries and petrochemical industries for the quantification of BTEX present in oily wastewater. This solution allows staying in compliance with wastewater discharge regulations from environmental protection agencies. The airmoVOC WMS with purge and trap has been applied for analysis of acrylonitrile. This polymer is used in plastics, fibers or as a component of additives to enhance oil recovery.

This fully automatic system, thanks to the integrated generators and internal calibration system for data validation, does not require specialised person to operate. Only power supply and sampling lines are required to operate and obtain reliable and representative analysis without molecules losses

Cylinder free analysers

When comparing lab GC-FID with auto-GC-FID used in the field for online monitoring systems, users may be concerned with the on-site use of hydrogen (H₂) and the complexity of cylinder management. Indeed, FID detectors require a H2/air flame and, in the case of cylinders, must be changed before exhaustion or else risk interrupting analyses while also decreasing the usable amount of gas. In terms of safety, gas cylinders are bulky and heavy so personnel must be trained on how to move and secure them.

To solve these problems, H₂ and zero air gas generators are used, instead of cylinders, in the first fully- automatic, standalone, cylinder-free, auto-GC-FID system manufactured by Chromatotec. Designed for industrial applications, the performance of the cylinder-free auto-GC-FID system is highlighted by its main features:

• Low cost of ownership: Only distilled water and ambient air are needed! The integrated generators provide the FIDs total gas consumption requirement: 30 mL/min H2 used as carrier gas instead of He (more expensive and difficult to supply) and 180 mL/min air.
• Improved safety: No compressed hydrogen cylinders are required.
• Complete autonomy: The FID can be operated continuously, avoiding the exchange of empty cylinders.
• Better sensitivity: Zero grade gases without hydrocarbon impurities for lower noise level and greater column protection.
• Saves space: The analyser and both generators are housed in an all-in-one wall-mounted cabinet.
• Enhanced ease of use: The measurement system performance evaluation is completed with internal calibration using NIST traceable permeation tube technology to provide automatic data validation.
• This fully automatic, user-friendly system does not require specialised personnel to operate.

The airmoVOC WMS with purge and trap has been applied in Jiangsu province industrial area for the speciation and quantification of BTEX present in ground water without interferents. This solution will improve water quality monitoring and allow staying in compliance with regulations from environmental protection agencies and will contribute to ensure the safety of drinking water.