Model gc 17a

To measure ethylene production and respiration rates, ten tomatoes randomly sampled from each treatment at each time point, were sealed in a container and held for 3 h at 25 °C. The headspace gas was collected and measured using a gas chromatograph (GC) (Model GC-17A, Shimadzu Co., Kyoto, Japan)^{66 (link)}. The ethylene production and respiration rates were expressed as µL kg⁻¹ h⁻¹ and mg kg⁻¹ h⁻¹ fresh weight basis, respectively.
Fruit firmness was determined using a digital force pressure tester equipped with a 2-mm-diameter round plunger with a flat surface (Model Instron 5542, Instron Co., USA)^{67 (link)}. Five fruits from each treatment at each time point were measured. Fruit firmness was expressed as mean Newtons (N).
Chlorophyll was extracted by grinding 1 g of fruit pericarp tissue in 5 mL of 80% (v/v) cold acetone and soaked for 30 min at 4 °C. For measurement of the lycopene, 2 g of fruit pericarp tissue was ground in liquid N₂ and extracted in 5 mL of dichloroethane for 3 h at 35 °C^{68 (link)}. The organic phase of both extracts was collected for detecting the absorbance at 484 and 652 nm using a spectrophotometer (UV2450, Shimadzu Co., Japan). The chlorophyll and lycopene content was expressed as μg g⁻¹ fresh weight.

The raw material for VFAs’ recovery was the fermentation product of a diluted alginate solution. Brown alginate (25 g) was dried, ground, and placed in a 500 mL reactor with 225 mL of 3% sulfuric acid solution, and maintained at 120 °C for 250 min [12 (link)]. The acid-pretreated solution was neutralized with calcium carbonate and filtered to yield a clear solution. Anaerobic fermentation was carried out for 15.5 days with microorganisms obtained from a municipal wastewater treatment plant in Busan, Korea, under the conditions listed in Additional file 1: Table S1). The VFA composition was determined by gas chromatography (Model GC-17A, Shimadzu, Japan,) using a capillary column (50 m × 0.32 mm × 0.50 µm) and a flame-ionization detector. The VFA composition was not significantly different from other studies regarding VFA fermentation, mostly ˂ 1%. The product composition of the other studies is summarized in Additional file 1: Table S2. The fatty acid production rate depended on the fermentation microorganism. As listed in Additional file 1: Table S2, the fermentation feed also affected VFA production, and the production rates among different fatty acids were largely influenced by the microorganism. High microorganism productivity improved economic feasibility of the VFA recovery process.

The volatile scent of blooming flowers was trapped on SPME (solid phase micro extraction), which was desorbed at the injection port at 210 °C for 1 min. The analysis was performed using Shimadzu gas chromatograph (Model GC-17A) coupled with Shimadzu model QP-5000 mass spectrometer (Tokyo, Japan) according to Farag et al., 2017^{49 (link)}. The identification of volatile components was established using AMDIS software (https://www.amdis.net) along with their retention indices (RI) as compared to n-alkanes (C6–C20). In addition to, mass spectrum matching with NIST, WILEY library database using matching score more than 800.

We analyzed the chemical components of oregano and thyme EOs using gas chromatography-mass spectrometry (GC-MS) on a Shimadzu Model GC-17A gas chromatograph interfaced with a Shimadzu model QP-5000 mass spectrometer (Shimadzu, Kyoto, Japan). We separated volatiles on a DB5-MS column with specifications: 30 m length, 0.5 mm i.d., and 0.25 μm film (J&W Scientific, Santa Clara, CA, USA). We injected the EOs at a split ratio of 1:10 for the 30 s. We used the following operating conditions: Injector 220 °C, column oven 38 °C for 3 min, then programmed at a rate of 12 °C min⁻¹ to 220 °C and kept for 2 min, His carrier gas at 1 mL min⁻¹. We adjusted the transfer line and ion-source temperatures to 230 and 180 °C, respectively. We operated the HP quadrupole mass spectrometer in the electron ionization mode at 70 eV and set the scan range at m/z 40–500. We identified the volatile components using the procedures described previously [41 (link)]. We identified the resultant peaks after first de-convoluted using AMDIS software (www.amid.net) and we subsequently identified the compounds by their retention indices (RI) relative to n-alkanes (C6–C20), and by matching their mass spectra to the NIST, WILEY library database (>90% match) as well as to those of authentic standards when available.

SPME fibers were desorbed manually at 210 °C for 1 min in the injection port of a Shimadzu Model GC-17A interfaced with a Shimadzu model QP-5000 mass spectrometer (Japan). The HP quadrupole mass spectrometer was operated in the electron ionization mode at 70 eV with a scanning range set at m/z 40–500 and a source temperature of 180 °C. Isolation and identification of volatile components were done according to [69 (link)]. Peaks were first de-convoluted using AMDIS software (http://www.amdis.net) and identified by its retention indices (RI) relative to n-alkanes (C6-C20), mass spectrum matching to NIST, WILEY library database (>90% match) and with authentic standards (whenever available).