Gc 450

For determination of the oxygen consumption we designed two assays. First we evaluated the depletion of the oxygen levels in the gas phase of culture flasks sealed with Suba-seal septa. Every hour we took a 0.5 ml gas sample from the growing culture and analyzed the oxygen concentration by gas chromatography (Varian GC-450) coupled to a molecular sieve column and a TCD detector. Oxygen depletion was linear until 10 hours growth. The rate of consumption was calculated as the amount of oxygen consumed in the gas phase normalized by the protein concentration of the culture. A measurement of the dissolved oxygen consumption was also carried out with a Clark-type electrode. After addition of 100 μl of bacterial culture into the chamber, containing 1.6 ml of NFbHP-Malate at 30°C, the consumption of dissolved oxygen in the medium was recorded until the polarizing voltage reached 0 (i.e. 0% oxygen saturation).

The gas phase was analyzed qualitatively for the presence of methane using a gas chromatography system (GC-450, Varian, Middelburg, The Netherlands) equipped with a molecular sieve column (CP81071: 1.5 m*1/8″ ultimetal molsieve 13 9 80–100 mesh) and a flame ionization detector.

Urine samples were collected in a polypropylene cup. During each IVF-ICSI cycle, at least one urine sample was provided just before egg-retrieved procedure. A handheld refractometer was used to assessed specific gravity (SG). The concentration of triclosan was measured using gas chromatography (Varian GC-450) coupled with tandem mass spectrometry (Varian 220-MS, ion-trap mass spectrometer as previously described (Jurewicz et al. 2019 (link))). External quality control was carried out by participation in the German External Quality Control Scheme (G-EQUAS), organized, and managed by the Institute and the Outpatient Clinic for Occupational, Social, and Environmental Medicine of the University of Erlangen-Nuremberg (Erlangen, Germany). Scheme, evaluation, and certification are based on the German Federal Medical Council (http://www.g-equas.de/). Analytical laboratory of the Department of Toxicology, Medical University of Gdańsk, successfully participated in this external quality check for triclosan.

Before the photocatalytic reduction of CO₂, 10 mg photocatalyst and 10 mL water were added into a septum-sealed borosilicate glass reactor with a volume of 140 mL. Then, the reactor was purged with CO₂ for the photoreduction experiment. A 300 W Xe lamp (Newport) was utilised as a light source, and the light output power was measured by a Newport 918-D calibrated photodetector. During the reaction, the products were analysed by GC (Varian GC-450) with a thermal conductivity detector (TCD, connected to a molecular sieve column) and a flame ionisation detector (FID, connected to a CP-SIL 5CB capillary column) containing a methanizer equipment. Ar gas was used as the GC carrier gas.
For the isotope-trace experiment, the same photocatalytic process was applied except ¹³CO₂ (¹³C 99%, Sigma-Aldrich) was used as the feed gas. The products containing C-isotope were analysed by GC–MS (Shimadzu QP-2010SE) with a molecular sieve 5 Å capillary column (for CO) or a Rxi-624Sil MS capillary column (for methanol). He gas was used as a carrier gas during the measurement.
The CH₃OH oxidation conditions: 10 ml H₂O, 0.12 µmol MeOH, 10 mg ^mCD/CN photocatalyst, 300 W Xenon lamp irradiation with 420 nm long-pass filter in 1 bar Argon atmosphere.

The methodological procedure described in a previous publication was used [6 (link)]. Approximately 50 mg of fat samples were precisely weighed into 20 mL capacity glass ampules. A volume of 0.1 mL of the hexane solution of the internal standard (heptadecanoic acid at a concentration of 10 mg/mL) was introduced to the fat sample [25 ]. The procedures for fat saponification and fatty acid esterification were conducted following previously established methodologies [26 (link),28 ,50 ].
Gas chromatography (GC) was carried out using a Varian GC 450 gas chromatograph equipped with a flame-ionization detector (FID) and a 30 m (0.32 mm i.d.) column coated with a 0.25 µm film of SelectTM Biodiesel for FAME. A temperature gradient was applied (200 °C for 10 min, then incremented by 3 °C/min to 240 °C, holding at 240 °C for 5 min). The injection port and detector temperatures were set at 250 °C and 300 °C, respectively, with a split ratio of 1:50. The flow rates were adjusted to achieve a ratio of gas flows (column + carrier gas):(detector supply):(air) at 1:1:10, with carrier gas (helium) at 28 mL/min, detector supply (hydrogen) at 30 mL/min, and detector supply (synthetic air) at 300 mL/min.
Quantitative analysis relied on calibration curves established for FAMES standard mixture (C14–C22) within the concentration range of 0.1–80.0 g/100 g.