Hp6890 gc system

Analyses using gas chromatography-mass spectrometry were carried out with an HP 6890 GC System (Hewlett Packard, Böblingen, Germany) coupled to a 5973 Mass Selective Detector (Hewlett Packard, Böblingen, Germany). The mass detector worked in the electron impact ion-isolation mode at 70 eV, the mass range was 10–600 units, and the ion source temperature was 230 °C. A total of 1 µL of extract was injected into the GC equipped with a 30 m × 0.25 mm i.d. capillary column with an HP-5MS ((5%-phenyl)-methylpolysiloxane, Agilent J and W GC column) with a coating thickness of 0.25 µm. Helium, at a constant flow rate of 2 mL/min, was used as the carrier gas, while chromatographic conditions were set as follows. Oven temperature was initially held at 40 °C for 3 min, and then increased to 180 °C at a rate of 5 °C/min, and, finally, increased to 250 °C at a rate of 10 °C/min. The equilibration time was 0.5 min. The components were identified by comparison of their mass spectra with those of the spectrometer database using the NIST library (National Institute of Standards and Technology, Gaithersburg, MD, USA), with probabilities higher than 80%. Each sample was analyzed three times.

The initial screening for determination of differences and/or similarities in the cuticle profiles of Bactrocera spp. was performed with a Hewlett Packard HP 6890 GC System connected to a Hewlett Packard 5973 Mass Selective Detector. For analyses, an HP-5MS capillary column (30 m × 250 μm i.d. × 0.25 μm film; Agilent Technologies, Santa Clara, CA, USA) was used. Temperature was programmed from 150°C to 300°C at a rate of 5°C/min with 10 min final hold at 320°C. Samples (1 μl) were injected using a splitless mode with He as the carrier gas (constant pressure, 1 ml/min). Electron ionization at 70 eV was used in the range from 25 to 600 m/z, with ion source temperature 250°C and quadrupole temperature 150°C.
Detailed identification and quantification of the components was performed by GC×GC/MS, using a LECO Pegasus 4D instrument (LECO Corp., St. Joseph, MI, USA) equipped with a non-moving quad-jet cryomodulator connecting the 1st and the 2nd columns. The methodology has been described in detail elsewhere [23 ,25 (link),26 (link)]. A series of n-alkanes (C₁₂–C₄₀; Sigma-Aldrich) was used to determine the retention indices for the analytes. The compounds were identified by a comparison of their MS fragmentation patterns and retention indices with values published previously [22 (link),23 ,26 (link),29 ,32 ,33 (link)].

Lipids were extracted from three S. alveolata whole individuals following Folch et al.51 (link). The lipids were placed at the top of a silica gel microcolumn (30 × 5 mm internal diameter; Kieselgel; 70–230 mesh [Merck, Lyon, France]; previously heated to 450 °C and deactivated with 5% water). Neutral lipids were eluted with 10 mL of chloroform/methanol (98:2, v/v), and polar lipids were eluted with 15 mL of methanol52 . Tricosanoic acid (2.3 μg) was added as internal standard. Polar lipids were transesterified at 100 °C for 10 min with 1 mL of boron trifluoride (12% Me–OH)53 . This transesterification produces fatty acid methyl esters (FAME) from the fatty acid esterified at the sn-1 and sn-2 position of diacylphospholipids, and the sn-2 position of plasmalogen PL. It also produces dimethyl acetals (DMA) from the alkenyl chains at the sn-1 position of plasmalogens54 (link). FAME and DMA were analysed in a HP6890 GC system (Hewlett-Packard) equipped with a DB-Wax capillary column (30 m × 0.25 mm; 0.25 μm film thickness; Agilent technologies). Peaks were analysed by comparison of their retention time with those of a standard 37 component fatty acid methyl ether (FAME) mix and other standard mixes from marine bivalves. Fatty acid contents were expressed as the mole percentage of the total fatty acid content. Total DMA was used as an indicator of the plasmalogen level.

The fatty acid composition of diets and tissues were determined by gas chromatography (Hewlett-Packard HP6890 GC system) equipped with a Chrompack Capillary Column (CP-Sil 88 column), as previously described [16 (link)]. Briefly, diets and tissues were homogenized (Bead Ruptor 12; Omni International) for 1 min and an alique of 0.5 g was sampled for fatty acid extraction. Liver tissues were extracted with chloroform:methanol (2:1, v:v). The extracted fat was saponified with methanolic potassium hydroxide and methylated with methanol solution (0.4 mol/L potassium hydroxide). Fatty acid methyl esters were determined by gas chromatography and results are expressed as a fraction of the total amount of fatty acid methyl esters.