Gc 14 gas chromatograph

The ethylene gas was obtained in the same way as the respiratory intensity and was measured by GC-14 gas chromatograph (Shimadzu, Kyoto, Japan) and repeated three times. The setup parameters and calculation formula were referred from Li Ling et al. [16 (link)] with some modification. The experimental parameters were set as follows: the chromatographic column was a GDX-502 stainless steel packed column; the detector used was a hydrogen flame ionization detector; and the carrier gas was N₂. The inlet temperature, column temperature box, and detector temperature were all set at 60 °C, and the unit was expressed in μL kg⁻¹·h⁻¹.
$$\mathrm{E}\mathrm{t}\mathrm{h}\mathrm{y}\mathrm{l}\mathrm{e}\mathrm{n}\mathrm{e}\mathrm{P}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n}=\frac{\mathrm{C}\times \mathrm{V}}{\mathrm{M}\times \mathrm{T}\times 1000}$$

in which C is the ethylene content in the sample gas, with the unit as µL L⁻¹;

V is the volume of the enclosed space, with the unit as mL;

M is the mass of fruits, with the unit as kg; and

T is the smothering time, with the unit as h.

To an essential oil sample (0.6 g) or each essential oil standards (0.02 g) (α-pinene, β-pinene, myrcene, limonene, γ-terpinene, cis-linalool oxide (f), cis-linalool oxide (f) linalool, α-terpineol, neryl acetate and geranyl acetate), n-hexane was added to a volume of 2.0 mL, and 0.8 mL of the essential oil sample solution was mixed with n-hexyl alcohol at an appropriate concentration (n-hexyl alcohol was added to 0.13 g of n-hexane to a volume of 20 mL) to establish an internal standard. The quantitative analysis of each sample was performed using the method described by Hosni et al. and Mohammadi et al., with minor modifications [17 (link),36 ]. GC analyses were conducted on a Shimadzu GC-14 gas chromatograph (Shimadzu Corporation, Kyoto, Japan), equipped with a flame ionization detector, and a Shimadzu C-R6A chromatopac integraph (Shimadzu Corporation, Kyoto, Japan). An Equity-5 nonpolar column (60 m × 0.25 mm, 0.25 μm film thickness) was used. The column temperature was programmed to rise from 75 to 200 °C at a rate of 2 °C/min. The injector and detector temperature were set at 250 °C. The flow of the carrier gas (N₂) was 50 mL/min. The injection volume for all samples was 0.5 μL of diluted oil in n-hexane (Merck KGaA, Darmstadt, Germany). The data were recorded as the average of three analyses.