Gcms qp2010s instrument

The method used to quantify polyhydroxyalkanoates content was adapted from a previously described method [23 (link)]. To determine the PHA composition and content, 500 µL of culture was centrifuged at 8000 rpm for 5 min. The pellet was resuspended with 500 µL of chloroform and added to a 10 mL screw cap glass tubes with 2 ml of a solution containing 1.94 mL of methanol, 0.06 mL of sulfuric acid, and 0.2 mg of toluic acid. The tubes were then placed in a thermostatically regulated bath at 100 °C for 210 min. After the reaction, 1 mL of distilled water was added and the tube was shaken vigorously. After phase separation, the organic phase (bottom layer) was removed and transferred to a small screw cap glass vial. The methyl esters were analyzed using gas chromatography using a SHIMADZU GC-MS QP2010S instrument (Shimadzu, Kyoto, Japan) equipped with an Optima ^® 5 capillary column (30 m/0.25 nm; Macherey-Nagels, Düren, Germany) and a flame ionization detector. Afterwards, 2 µL of the organic phase was analyzed after spitless injection. Helium (20.2 mL/min) was used as the carrier gas. The temperature of the injector was 250 °C.

The concentrations of acetone, isopropanol, ethanol, and acetate were determined by GC–MS analysis using a Shimadzu GCMS-QP2010S instrument. Supernatants from bacterial cultures were diluted 1:10 in 100% methanol spiked with 5.5 mM 1,3-propanediol as an internal standard, and were fractionated on an InertCap FFAP capillary column (0.25 mm × 30 m, 0.25 µm film thickness; GL Sciences, Torrance, CA, USA). A 1-µl sample was evaporated at 200 °C, and the following temperature profile was then applied: initial 3 min hold at 50 °C, temperature gradient (35 °C/min) to 220 °C, and final hold at 220 °C for 2 min. The eluate was ionized at 1 kV and the total ion count was monitored. Absolute concentrations of analytes were calculated using corresponding calibration curves.

The B. ogadensis essential oils were analyzed by chiral GC-MS as previously reported [41 (link)]: Shimadzu GCMS-QP2010S instrument (Shimadzu Scientific Instruments, Columbia, MD, USA), Restek B-Dex 325 capillary column (30 m × 0.25 mm × 0.25 μm film) (Restek Corporation, Bellefonte, PA, USA). Enantiomers of monoterpenoids identified by comparison of retention times with authentic samples (Sigma-Aldrich, St. Louis, MO, USA) and percentages determined based on peak areas. A representative chiral gas chromatogram is shown in Supplementary Figure S2.