Db 23 gas chromatography column

We examined seasonal changes in the fatty acid proportion of ovary lipids by GC/MS. Triacylglycerol (TAG) and phospholipid (PL) were esterified by incubation with methanol containing 5% hydrochloric acid at 50°C for 30 min. Analysis of fatty acid methyl esters was performed on a gas chromatography (Agilent Technologies 6890N)/mass spectrometry (Agilent Technologies 5975B) system using with a DB-23 gas chromatography column (60 m × 0.25 mm i.d. and 0.15-μm film thickness [Agilent technologies]). Helium (carrier gas) was passed through the column at a constant linear velocity of 40.0 mL/min, and the split ratio was 50. The initial oven temperature was maintained at 50°C for 1 min, increased to 175°C at a rate of 25°C/min, increased to 230°C at a rate of 4°C/min, and then maintained for 5 min. The temperatures of the inlet, interface, and ion source were 250°C, 280°C and 230°C, respectively. Elec- tron impact (EI, 70 eV) was used as the ionization mode. MS data were analyzed with Agilent GC/MSD ChemStation software. We measured the area of all fatty acids whose area was more than 3% of the largest one observed. MS fragment data were matched against entries in NIST atomic spectra database 2.0.