Hp molesieve

The 0.5 ml gas samples were collected and injected by gas-tight syringes (the VICI Pressure-Lok Precision Analytical Syringe A-2 Series (050033), 1 ml), and the 2 ml liquid samples were collected and placed in a headspace sampler; then the samples were analyzed by gas chromatography-mass spectrometry (8890-5977B GC-MS instrument, Agilent Technologies, USA) equipped with commercial capillary columns. The column was maintained at a certain temperature for 15 min, and the flow of the carrier was 0.8 ml l⁻¹. The temperatures of the injector, EI source, and GCITF were set to be 200, 200, and 250 °C, respectively. The mass-to-charge ratio of the mass scanning mode was set from 2 to 70. The GC-MS was operated the post-run after each injection (the temperature of the column oven increased to 300 °C with a rate of 30 °C and then maintained at 300 °C for 10 min). Developing a suitable programmed temperature rise process can further shorten the detection time.
The information of the columns are listed below:
(HP-Molesieve, 5A molesieve, 19091S-MS8, 30 m × 0.32 mm × 25 μm, Agilent Technologies, USA; HP-PLOT/Q, Bonded polystyrene-divinylbenzene, 19091P-QO4, 30 m × 0.32 mm × 20 μm, Agilent Technologies, USA; HP-FFAP, Modified polyethylene glycol, 19091F-413, 30 m × 0.32 mm × 20 μm, Agilent Technologies, USA).

The reaction products were analyzed by two gas chromatographs: (1) a gas chromatograph (GC) Agilent Technology model # 6890N, and (2) a gas chromatograph-mass spectrometer (GC-MS) HP model # G1800C. The GC was connected on-line with the reactor. This GC had two detectors: (1) flame ionization detector (FID) and (2) thermal conductivity detector (TCD). The TCD analyzed light hydrocarbon products (C1–C4), CO, CO₂, and water. The FID analyzed heavier hydrocarbons (C5–C13). The GC has six 30-m mega-bore capillary columns: one methyl silicone HP-1, two HP Plot Q, one HP Mole Sieve, one HP Plot Alumina, and one 5% phenyl methyl silicone HP-5 (Agilent Technologies, Santa Barbara, California). All columns have about 40- to 50-μm-thick adsorption phases. The GC has three valves that split the carrier gas into six columns (Fig 2), which better separate the samples and consequently give more accurate results. All the reaction products were analyzed with this chromatograph; however, heavier hydrocarbons (C5–C13) were lumped by carbon number. To identify all the isomers in the liquid phase, the GC-MS analyzed the liquid product samples. Before the analysis, all reaction products were cooled to 0°C to ensure that all C5+ hydrocarbons were in the liquid phase. A GC-MS analysis of the liquid phase typically determined that the liquid samples had over 100 compounds.

The isotope-labeling experiment was conducted by using ¹³CO₂ (isotope purity, 99% and chemical purity, 99.9%, Tokyo Gas Chemicals Co., Ltd.) as the carbon source. Typically, 10 mg of photocatalysts, 2 mM of [Ru^II(bpy)₃]Cl₂·6H₂O, 10 mM of BIH, 30 mL of acetonitrile and 100 μL of water were loaded into the reaction cell. The protocol of ¹³CO₂ photoreduction was the same as that mentioned above. The gas products were analyzed by gas chromatography–mass spectrometry (JMS-K9, JEOL-GCQMS, Japan and 6890 N Network GC system, Agilent Technologies, USA) equipped with the column for detecting the products of ¹³CO (HP-MOLESIEVE, 30 m × 0.32 mm × 25 μm). Helium was used as carrier gas. The column was maintained at 60 °C for 20 min, and the flow of the carrier was 0.5 ml L^–1. The temperatures of the injector, EI source, and the GCITF were set to be 200, 200, and 250 °C, respectively.