https://doi.org/10.3390/foods11233916
“The analyses were performed on a GC 7890B gas chromatograph (Agilent Technology, Santa Clara, CA, USA) equipped with a flame ionization detector (FID). A DB-WAX column (60 m × 0.25 mm i.d., 0.25 μm film thickness, Agilent Technology, Santa Clara, CA, USA) was operated under programmed temperature conditions: 35 °C held for 8 min, 35–40 °C at 2.5 °C/min, 40–100 °C at 5 °C/min, 100–200 °C at 10 °C/min, 200–220 °C at 20 °C/min and held for 10 min (detector temperature of 250 °C, injector temperature of 230 °C), and nitrogen gas carrier gas (1.6 mL/min). Three internal standards were used in this study: amyl acetate (IS1, 10 μL, 10.33g/L), 2-methyl hexanoic acid (IS2, 10 μL, 14.00 g/L), and tertiary amyl alcohol (IS3, 10 μL, 8.05 g/L). The mixed standard solutions (1 mg/mL) were prepared in absolute ethanol and diluted with 53% (v/v) ethanol to the following concentrations: 50,000, 10,000, 5000, 1000, 500, 100, 50, 20, 10, and 1 mg/L. Each working standard solution (1 mL) was spiked with 10 μL IS1-3. Afterward, a 1 μL sample was then directly injected in a split mode (split ratio was 50:1). The LOD and LOQ values of standards were determined at their concentrations when their signal-to-noise ratios (S/N) were 3 and 10, and calibration curves were drawn using the response ratio between the target aroma and internal standards versus the ratio between their concentrations. Detailed information is provided in Supplementary Table S1. Every 1 mL SAB sample was spiked with 10 μL IS1-3, and then GC-FID quantification was performed the same way as the working standards. The signal was recorded and processed with OpenLab CDS (Agilent Technology, Santa Clara, CA, USA) software.”