Db 225 capillary column

Oils extracted from raw fish were use for the determination of fatty acid profile. Fatty acids composition of the fish oil were determinate after conversion of their fatty acid methyl esters (FAME) using borong trifluoride methanol method. The lipids were saponified and esterified for fatty acid analysis by the method described by Metcalfe, Schmitz, and Pelka (1966). The GC‐FID analyses were performed with an agilent (Agilent Technologies, Palo Alto, CA) 7890A series gas chromatograph equipped with FID detector using a DB‐225 capillary column (30 m × 0.25 mm, 0.25 μm of film thickness). The column temperature was initially maintained at 160°C for 2 min, increased to 220°C at 5°C/min and maintained for 10 min at 220°C. The carrier gas was nitrogen at a flow rate of 1.5 ml. The injector and detector temperatures were maintained at 230 and 250°C, respectively, with a split ratio of 50:1. Identification and quantification of fatty acids were based on comparison of their peaks with the relevant peak areas of the corresponding standard fatty acids where each fatty acid was then expressed as a percentage of the total fatty acids quantified.

Fatty acid methyl esters were prepared using methanol/hydrochloric acid. The fatty acid methyl esters were analyzed by a Hewlett–Packard model 5890 gas chromatograph equipped with a flame ionization detector and separated on 30 m × 0.536 mm × 0.50 μm DB-225 capillary column (Agilent). The injector was set at 250 °C, and the detector was at 300 °C. The temperature program was as follows: initial temperature of 70 °C for 2 min, rate of 20 °C/min for 5 min (final 170 °C), rate of 2 °C/min for 10 min (final 190 °C), hold at 190 °C for 5 min, rate of 2 °C/min for 15 min (final 220 °C), and hold at 220 °C for 5 min. The identity of fatty acid methyl esters was determined by comparing their retention times with fatty acid methyl ester standards (Matreya). The compositions were expressed as weight percentages.

The identification and quantification of the monosaccharides in CPOP was achieved by gas chromatography (GC). Polysaccharides (10 mg) were hydrolyzed with 2 M TFA at 100 °C for 2 h, followed by drying, reduction with NaBH₄, and acetylation with Ac₂O-NaOAc at 120 °C for 1 h [44 (link)]. The Ac₂O was denatured with ice water, and the resulting alditol acetate extracted with chloroform and examined by GC. The following neutral monosaccharides were used as references: rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose. GC was performed on a Varian model 3300 instrument (Varian, Palo Alto, CA, USA) equipped with a DB-225 capillary column (Agilent, Beijing, China, 30 m × 0.25 mm inside diameter (i.d.)) and detected with a flame ionization detector (Agilent, 260 °C).The column temperature was increased from 150 to 200 °C at the rate of 4 °C/min and then held for 5 min. The quantification was carried out from the peaks area, using response factors from standard monosaccharide.

Neutral sugar content in purified AXs was determined by gas chromatography (6890N GC, Agilent Technologies, Santa Clara, CA, USA) with a flame ionization detector and a DB 225 capillary column (30 m × 0.32 mm internal diameter, 0.15 μm film thickness; Agilent Technologies, Santa Clara, CA, USA) after hydrolysis and derivatization into alditol acetates as described elsewhere [18 (link),19 (link)].

Both 20 mg raw and pretreated PHs were used to analyze chemical composition. The structural carbohydrates, ash, and lignin analysis procedure of all biomass samples were measured according to the NREL Laboratory Analytical Procedure (LAP) [19 ]. And organic solvent extractives (OSE) were analyzed with TAPPI Standard Methods [20 ]. The raw and pretreated (HPAC and popping) PHs were analyzed for their neutral sugar content using gas chromatography (GC) [13 (link)]. The samples were analyzed via GC (GC-2010; Shimadzu, Otsu, Japan) using a DB-225 capillary column (30 m × 0.25 mm i.d., 0.25 μm film thickness, J&W; Agilent, Folsom, CA, USA) operated with helium. The operating conditions were as follows: injector temperature of 220°C, flame ionization detector (FID) at 250°C, and an oven temperature of 100°C for 1.5 min with a constant increase of 5°C/min to 220°C.

The quantification of neutral sugars was performed according to what has been reported by Pinto et al. [4 (link)]. Mannans extracts were hydrolyzed using 72% H₂SO₄ (3 h, room temperature) followed by H₂SO₄ 1 M (1 h, 120 °C) [40 (link)]. Neutral sugars were derivatized to their alditol acetates, as described by Blakeney et al. [41 (link)], and analyzed by gas-chromatography-flame ionization detection (GC-FID) (Agilent Technologies, Inc., Santa Clara, CA, USA) in a 7890B GC System with a DB-225 capillary column (30 m length, 0.25 mm diameter, 0.15 µm thickness). The carrier gas was nitrogen at constant flow (1 mL/min), and hydrogen (30 mL/min) and compressed air (400 mL/min) were also used in the analysis. A split ratio of 1:60 was also used, and the injector and detector temperatures were set at 220 °C and 230 °C, respectively. The oven temperature was first set to 200 °C, and kept at that temperature for 2 min, then raised to 220 °C at 40 °C/min, with a hold time of 7 min, followed by a second linear increase to 230 °C at 20 °C/min, holding for 5 min. The total run time is 15 min.