Title : Measurement of aldehydes from ambient air and method validation and proficiency testing using a dynamic test gas facility
In the field of occupational health and safety, the measurement of hazardous substances is one of the cornerstones in the prevention of occupational diseases. Aldehydes are found in many workplaces mainly due to their use as disinfection agents and for the fixation of biological samples. As Formaldehyde is classified as carcinogenic to humans (IARC group 1), routine monitoring of aldehydes is of major importance for workplace safety. For method validation and regular proficiency testing for internal and external partners, the Institute for Occupational Safety and Health (IFA) provides proficiency testing schemes for various hazardous substances including selected aldehydes at its dynamic test gas facility. Currently, the setup of the test gas facility allows simultaneous sampling for up to 25 participants with a total test gas flow of up to 12 m³/h. The provided test gases must meet high requirements regarding correctness, homogeneity, precision, and stability. To ensure the quality of the test gas in real time, Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) has been established to monitor the quantitative test gas compositions. With the help of this new technique, short-term changes in the test gas composition can be observed in real time in contrast to the previously utilized measurement of offline-control samples by HPLC. This made it possible to verify a newly designed dosing system for the test gas generation of substances with high vapor pressure such as acetaldehyde and propionaldehyde by SIFT-MS. The special challenge here is that the entire dosage must be carried out in a cooled environment to avoid vaporization of substances in the tubing of the dosing system. By combining three individual components, a novel system for generating test gases was developed. The system is modularly composed of a microfluidic pressure-based pump system, a high precision cooling unit and a modified gas chromatographic inlet system. The system is suitable to produce an aldehyde test gas with the required quality in the dynamic test gas facility of the IFA. The suitability of the system was successfully demonstrated by parallel investigations using SIFT-MS and classical offline-HPLC analysis.
- Techniques for the air monitoring of aldehydes
- Importance of method validation during method development for air sampling techniques
- Advantages of selected ion flow tube mass spectrometry (SIFT-MS) for the monitoring of test gas in real time
- Advanced generation of dynamic test gas atmospheres.