Gc 2014 series

After electrochemical reaction in the electrolyzer the outgoing gas stream was mixed with a constant flow of N₂ as an internal standard (16 mL min⁻¹) and CO₂ (150 mL min⁻¹) that has been purged through the headspace of the catholyte compartment in order to collect gaseous products that were released at the catholyte side during operation. This mixture of gases was introduced into a gas chromatograph (Shimadzu, GC 2014 series) in the following denoted as GC. The GC was equipped with a thermal conductivity detector (TCD) used in the quantification of H₂ and N₂ concentrations, as well as a flame ionization detector (FID) that was used for quantification of methane, ethylene and CO. For the detection of CO by the FID a methanizer has been used for the thermal reduction of CO to CH₄ prior to its detection. Determination of the absolute volumetric flow after electrolysis has been conducted based on changes in the concentration of N₂ standard as detected by the TCD.

The GC-MS analysis was performed in a Shimadzu GC 2014 series equipped with a flame ionization detector. A DB-35 capillary column (30 mm × 0.25 mm × 25 μm). The initial temperature was 80°C for 4 min after injection, increased to 280°C with a final hold at 280°C for 25 min. The injector and detector temperature were maintained at 270°C. Helium was used as a carrier gas at a flow rate of 0.7 mL/min.