7890b gc fid

The headspace of sulfur volatile-exposed and non-exposed orange plants was collected on HayeSep Q adsorbent using dynamic headspace sampling in a climate-controlled cabinet for 6 h [14 (link)]. The traps were extracted with 500 μL hexane containing nonyl acetate (1.75 ng μL⁻¹) as the internal standard, and concentrated to 100 µL for GC-MS analysis. The samples were injected on an Agilent 8890 GC-5977B MSD equipped with a HP-5MS column (30 m × 0.25 mm × 0.25 μm, Agilent Technologies, Santa Clara, USA) with spitless mode (helium, 1.0 mL min⁻¹). Column temperatures were programmed from 40 °C for 1 min, raised to 200 °C at 8 °C min⁻¹, isotherm of 1 min, then raised to 280 °C at 20 °C min⁻¹, and isotherm of 5 min. Injector and detector temperatures were 250 °C and 280 °C, respectively. Volatile compounds were identified according to their RIs (calculated using C7−C30) and mass spectra stored in the NIST library, and were identified by co-injection of authentic standards. The quantification of identified volatiles was conducted on an Agilent 7890B GC-FID equipped with an HP-1 column (30 m × 0.32 mm × 0.25 μm), using the same temperature programs as in the GC-MS analysis. Six independent plant replicates were used for each treatment.

A UV-Vis spectrophotometer (Shimadzu, Kyoto, Japan), a Zeta Sizer Nano ZS (Malvern Instruments, Malvern, UK), a lyophilizer (Biobase, Shandong, China), a centrifuge (Universal 320R, Tuttlingen, Germany), a homogenizer (Bandelin HD, Berlin, Germany) and an Agilent 7890B GC-FID coupled with an Agilent 5977E MS Detector (Santa Clara, CA, USA) were used. PLGA (CAS no. 26780-50-7), polyvinyl alcohol (PVA) (CAS no. 9002-89-5), dichloromethane (DCM) (CAS no. 75-09-2), calf thymus DNA (CT-DNA) and ethidium bromide were purchased from Sigma Aldrich. Tris base, Ethylenediamintetraacetic acid (EDTA), sodium chloride (NaCl), hydrochloric acid (HCl), and sodium hydroxide (NaOH) were purchased from Merck Millipore (Burlington, MA, USA).