A new sampling system is now available for routine measurements of 14CH4. The new system enables extraction of carbon from CH4 while sampling in the field, reducing the sample processing in the laboratory and allowing collection of a hundred liters of air onto a 0.5 g zeolite trap. This new system greatly facilitates 14CH4 measurements, and it represents a break-through into the detection and quantification of methane emissions. An image of the methane sampling device is attached. The whole system fits well into a box of 80 x 40 x 30 cm and runs either on 115/230 V AC or 48 V DC provided by a battery pack.
Major parts of the system are: 1) Nafion dryer (mostly hidden underneath), 2) Pumps (partially hidden), 3) CO2 trap, 4) Flow controller, 5) Furnace for CH4 combustion, 6) Sample trap with Peltier coolers, 7) CO2 sensor
The new sampler is novel and one of its kind. The main features are 1) the CH4 carbon extraction while sampling, which greatly reduces the sample processing at the radiocarbon laboratory; 2) the system portability; 3) the fact that the sampler enables collection of several samples a day, and 4) that it is interfaced directly with leading-edge accelerator mass spectrometry facilities for radiocarbon measurements in the Ion Beam Physics group.
The use of the new sampler opens a new research field. 14CH4 measurements were not carried out routinely, and only by very few laboratories worldwide, due to the complexity of such measurements. The system, being very user friendly and enabling collection of small samples, will expand the capacity of 14CH4 measurements, providing insights into the methane budget. The sampler also enables high precision measurements (5‰), better than the most recent methodologies used for 14CH4 analysis, and therefore allows a more accurate quantification of methane emissions. The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
A first inter laboratory comparison has been performed, between the extraction system for 14CH4 analysis at ETH and at the University of Bern. The 14CH4 values measured from the same reference gases are comparable, showing that the new technology developed in this project produces results as accurate as previous techniques, which have been already published.
Secondments
The researcher has visited the AMS laboratory of the University of Bern (LARA), and she has been trained for the extraction of the sample for 14CH4 analysis. This secondment has been extremely useful, because it gave to the researcher the opportunity to compare different techniques and have a better understanding of what is needed for a greater accuracy of the measurements. With the secondment at EMPA , the researcher learnt the use of the atmospheric model FLEXPART. The researcher has now all the tools to run the model, although she is not very proficient due to the lack of time for running the simulations.
The system is currently available at LIP, laboratory of Ion Beam Physics, and it will be employed in future PhD and master projects at ETH.
Researcher's training
The researcher has been trained on the use of MICADAS AMS system for 14C analysis, on the sample preparation for the gas interface of the Micadas system, and on the construction of some parts of the system, such as a little furnace and sample traps of zeolite (T1). The researcher started also the training on the use of the model FLEXPART and she attempted few simulations (T2).
