Db wax

For fatty acid (FA) analysis, the A. platensis biomass was transmethylated with 2% H₂SO₄ in a methanol/toluene mixture (90:10, v/v) at 80 °C for 1.5 h. Heptadecanoic acid (C17:0) was added as an internal standard. Then, an analysis of fatty acid methyl esters (FAMEs) was carried out using a Shimadzu-2014C gas chromatograph, equipped with a flame ionization detector (Shimadzu, Kyoto, Japan) and fused silica capillary column DB-WAX (30 m × 0.25 mm). The injection port temperature was 260 °C. The column temperature was programmed from 190 °C (with a hold of 5 min) to 250 °C (with a hold of 5 min), at a rate of 5 °C min⁻¹. The amount of individual FAMEs was calculated according to the method described by Li et al. [32 (link)].

Ostrinia species were identified by visual appearance and sex pheromones of the virgin females. Sex pheromone components of O. furnacalis and O. scapulalis are mixtures of (E/Z)−12-tetradecenyl acetates (E/Z12-14:OAc) and (E/Z)−11-tetradecenyl acetates (E/Z11-14:OAc), respectively^{25 (link)}. The hexane extract of a pheromone gland was individually analyzed using a gas chromatograph coupled to a mass spectrometer (QP2010 SE GC–MS, Shimadzu, Japan) equipped with a capillary column (DB-Wax, 0.25 mm i.d. × 30 m; Agilent Technologies, USA). The initial column oven temperature of 80 °C was held for 2 min, then raised at 8 °C/min to 240 °C and held for 2 min. The flow rate of the carrier gas (helium) was 1.0 mL/min. Mass spectra were recorded in the electron ionization mode at 70 eV. Retention time and diagnosis ions (m/z 61 and m/z 194 for [M- 60] ⁺; i.e., elimination of acetic acid) of peak were compared to authentic standard.

Volatile compounds of Nang roasted oyster cuts were analyzed according to the Liu et al. [17 (link)] method with minor modification using GC-MS (QP2010 Shimadzu, Kyoto, Japan) with a DB-WAX (30 mm × 0.25 mm × 0.25 μm). The carrier gas velocity was 1 mL/min. The oven temperature was maintained at 40 °C for 3 min, then heated to 120 °C at 5 °C/min, and finally heated to 200 °C at 10 °C/min, holding for 13 min. Ion source temperature was 200 °C. The scan mode was used to collect signals, and the scan range was 35–500 m/z. Volatile flavor compounds were qualitative identified by both the mass spectrometry database (NIST) search and linear retention index (LRI) compounds. The LRI was calculated by the retention time of n-alkanes (C₇–C₄₀) as in Equation (1): $\mathrm{LRI}=100n+100(t_x-t_n)/(t_{n+1}-t_n)$
where t_x is the retention time of compound x; t_n and t_{n +1} are the retention times of alkane n and alkane n + 1 (t_n < t_x < t_{n +1}), respectively. n and n + 1 are the numbers of carbons in alkanes n and n + 1 closest to the retention time of compound x.
The contents of volatile flavor compounds were quantitatively calculated by comparing their peak areas with that of the internal standard.