Gcms qp2010 plus gas chromatograph

Three portions of approximately 300 g of ground dried leaves were extracted for 2.5 h in a steam distillation glass distiller. The oil samples were pooled in ethyl ether, dried over anhydrous Na₂SO₄, filtered, and evaporated under vacuum and at low temperature, yielding 7.56 g (0.84% w/w) based on dry weight.
For the oil analyses by GC–MS (Shimadzu GCMS-QP2010 Plus Gas Chromatograph), a non-polar Rtx-5MS column (30 m × 0.25 mm × 0.25 μm) and the following analytical conditions were used: split ratio of 1/20, 250 °C for the injector, 250 °C for the ion source, and 280 °C for the interface. The oven temperature was programmed to 60 °C for the first 5 min, increasing at a rate of 3 °C/min to reach the final temperature of 240 °C. The components were identified based on the relative retention indices calculated using a series of n-alkanes (C8–C19) and the mass spectra from the apparatus database, followed by comparison with the published data [8 (link),17 ,18 ].

After microbial analysis, the rest of fresh musk was dried by exposure to phosphorus pentoxide (P₂O₅). We weighed the musk every 30 minutes until its weight ceased to change. Because a very small amount of musk remained for the mated group after bacterial DNA extraction and musk dehydration so we pooled three samples together (taking 0.07 gram of each sample, total 0.21 gram). After blending, each 0.1 gram of musk was dissolved in 2.5 ml absolute ethyl alcohol (purity > 99.7%) or 2.5 ml diethyl ether (purity > 99.5%), then extracted by ultrasonic for two hours. The dissolved samples were centrifuged at 13000g for 5 minutes and the liquid supernatant was used for chemical components analysis. The same method was applied for unmated (sample UM1, UM2 and UM3) males.
A Shimadzu GCMS-QP 2010 plus gas chromatograph (Shanghai, China), coupled to a Shimadzu QP 5000 mass spectrometer which was equipped with a split/split less injector and a DB5-MS column [(30 m × 0.25 mm i.d., 0.25 mm film thickness), (Agilent J&W, Agilent Technologies, CA, USA)] was used for the chromatographic analysis of the targeted compounds. The mass spectral data base NIST08.LIB was used to analyze the data. The confidence coefficient of the data above 80% was adopted.

Volatile organic compounds (VOCs) produced during the ozonation process were identified by thermal desorption unit ATD 650 (Perkine Elmer Corp., Shelton, CT, USA) combined with a GC-MS-QP2010 Plus gas chromatograph (Shimadzu, Kyoto, Japan) equipped with a DB-5MS 60 m × 0.32 mm × 0.5 µm column (Agilent Technologies, Santa Clara, CA, USA). ATD 650 was connected to GC-MS through a valve and a transfer line maintained at 210 and 215 °C, respectively. The conditions employed for the thermal desorption system were as follows: the desorption temperature and time were 250 °C and 10 min, respectively, the trap heat and cool temperature were 280 and −25 °C, respectively. Argon gas was used as the carrier gas with a flow rate of 1.5 mL min⁻¹. The sequential programmed linear temperature was used in ATD 650 system as; (1) 5 °C min⁻¹ to 120 °C (hold for 2 min); and (2) 10 °C min⁻¹ to 260 °C (hold for 5 min). The ion source temperature was maintained at 200 °C and GC oven temperature was 40 °C (hold for 2 min).