As part of WP3 “Analytical methods for tailored requests”, our Swiss colleagues from Tofwerk visited Wook K plus facilities in Vienna (Austria) on 17-19 July, 5 August and 18 September 2024 to carry out the installation and training on the Vocus CI-TOF (Chemical Ionisation – Time of Flight).
The Vocus CI-TOF instrument will be used to analyse Volatile Organic Compounds (VOC) emissions from Wood Polymer Composites (WPC) at the ppb level. At Wood k plus, it will be used to complement standard emissions testing, to find substances at very low levels that may be missed by traditional methods. It can also be used to monitor processes in real time (such as the heating cycle of a polymer, for example, when a car gets very hot in the summer and the interior emits more VOCs), which has not been possible with conventional methods. Ultimately, it could replace parts of existing methods and reduce analysis time for certain substances. The focus here is on toxic substances (e.g., benzene, etc.).
To measure at the ppb level, the entire measurement setup must be very clean, and to monitor on-line processes, the instrument must be calibrated frequently. Because of this, and because Wood k plus had never worked with an instrument like this before, they needed training on how to use the instrument in general and how to ensure this high sensitivity. Because this instrument does not separate substances prior to analysis, post-measurement data analysis is much more complex than in standard emissions testing. In particular, to find compounds that were not expected (untargeted analysis), the amount of data to be processed is quite large. For this reason, Wood k plus will receive ongoing training and support from Tofwerk’s data analysis experts. Our Austrian colleagues will also try out different modes of analysis within the instrument (different reactors), which will allow the analysis of different groups of compounds.
The instrument was supplied by Tofwerk, Switzerland, and installed in the emission test laboratory of the IQEC (Indoor Quality and Emission Control) working group of Wood K plus at the Technical University of Vienna. Assembling the individual parts of the instrument was helpful to get a first impression of the hardware and the measurement setup. Once the instrument was set up, the in-depth training began. The first module included a detailed overview of the instrument hardware components, followed by knowledge transfer on the concept of Time-Of-Flight (TOF) mass spectrometry and ionisation using the Vocus reactors. Further instrument maintenance, basic troubleshooting, quantitation and calibration were also discussed. The comprehensive introduction given by the Swiss colleagues was followed by initial test measurements, during which the Wood K plus team had the opportunity to take their first steps operating the instrument’s control panel (Tweb EXPLORE). Experiments were then carried out using a combination of micro-chamber and emission test chamber sampling with the Vocus CI-TOF. Different amounts of wood and polymer samples were measured using different airflow rates through the test chamber. The data collected was used to train participants in the use of TOF data visualisation and interpretation software (Tofware). Due to the complexity of the data analysis and the large amount of data collected, a further data analysis training day was arranged to review the steps after some practical experience.
A total of three Wood K plus employees were trained in the use of the Vocus CI-TOF instrument. The handling the instrument, the navigation of the instrument’s control panel (Tweb EXPLORE) and the operation of the post-processing software (Tofware) were thoroughly practiced.
The results of the test measurements will be used as a reference for future work in the project. The data collected will be used to estimate suitable sample amounts per chamber and appropriate airflow rates. Future measurements can then be based on these results.
Further test measurements on different WPC samples are planned for the coming months. The first set of samples will be used to collect data from simple heating cycles. This data will then be used to adapt and refine the measurement procedure for future measurement tasks. The laboratory workstation does not have a suitable exhaust port to connect the instrument’s exhaust. In order to switch from the Vocus PTR (Proton Transfer Reactor) to the Vocus AIM (Adduct Ionisation Mechanism) reactor, additional equipment is required to ensure a safe measurement environment. Therefore, Tofwerk has agreed to supply a functional filter system for in-lab waste gas treatment, which will be installed before switching.
