Using an EA (elemental analyzer) to measure DOC ∂13C скачать в хорошем качестве

Using an EA (elemental analyzer) to measure DOC ∂13C

An elemental analyzer (EA) can be modified to measure DOC. If coupled to an isotope ratio mass spectrometer (IRMS), DOC ∂13C can be measured. The two He lines of the EA are used. One of them is connected to an oxidation tube, filled with platinum beads at 680oC. The water sample (e. g. 1 mL) is injected directly in this tube, where catalytic platinum oxidation takes place and all carbon is converted to CO2. All gases and condensed water are carried to a liquid trap, where liquid water remains and but CO2 leaves. The carrier gas passes through halogen and water traps, to arrive to a cryotrap, where CO2 from the sample is accumulated. By changing a 6-port valve, the second helium line from the EA now carries the trapped CO2 to the IRMS. This configurations prevents excess O2 from the oxidation tube to reach the IRMS. The N2 used to dry the sample in the nafion trap os also used to purge the sample to remove DIC. The liquid trap is emptied periodically using a syringe with a 3-way valve, like the one for the DIC setup. OSMAR and AutoIt are used to automate the process. OSMAR: bit.ly/2QVnDJU Autoit: is.gd/labautobook Open-source autosamplers: bit.ly/3hfA15t **