GC/MS analyses of MSG extracts were carried out with an Agilent 6890 N GC interfaced to an Agilent 5975C mass-selective detector (Agilent, Santa Clara, CA, USA). Extracts were run on DB-Waxetr and DB-23 columns (30 m×0.25 mm×0.25 μm film thickness; J&W Scientific, Folsom, CA, USA). Injection was splitless and helium was the carrier gas (1 ml/min). Injector temperature was 250°C, and the column temperature was 40°C for 2 min, rising to 220°C at 10°C/min and then held for 10 min. Electron impact mass spectra were monitored at 70 eV in the mass range of 40–300 amu. Chemicals from the extracts were identified by comparison of their retention indices (RIs) relative to n-alkanes and mass spectra with those of authentic standards on the two columns. Quantities of compounds were estimated by using synthetic hexyl butyrate as an external standard.
Determination of double bond positions in unsaturated compounds of MSG extract was accomplished by reaction with DMDS. For the DMDS derivatization of a 10-female gland extract of A. lucorum, we followed the procedure described by Buser et al. [17 ]. The DMDS adduct was then analyzed by GC/MS on the DB-23 column under the same conditions as above.
Determination of double bond positions in unsaturated compounds of MSG extract was accomplished by reaction with DMDS. For the DMDS derivatization of a 10-female gland extract of A. lucorum, we followed the procedure described by Buser et al. [17 ]. The DMDS adduct was then analyzed by GC/MS on the DB-23 column under the same conditions as above.