Gcms qp2010 plus ei

Dry matter, nitrogen, crude ash, crude fiber, and ether extract contents of the diets were determined using the standard methods 934.01, 984.13, 942.05, 978.10, and 920.39 of the Association of Official Analytical Chemists [30 ], respectively. Fatty acid content of the feeds and each diet component was determined by base- and acid-catalyzed methylation, as described by Czauderna et al. [31 ], followed by quantification using capillary gas chromatography coupled with mass spectrometry (GC-MS), as described by Rozbicka-Wieczorek et al. [9 (link)] GCMS-QP2010 Plus EI (Shimadzu, Tokyo, Japan) equipped with a BPX70 fused silica column (120 m × 0.25 mm inner diammeter × 0.25 μm film thickness; Phenomenex, Torrance, CA, USA), a quadruple mass selective detector (Model 5973 N), and an injection port was used, with helium as the carrier gas. Fatty acid methyl esters (FAMEs) were identified by the comparison of electron ionization spectra of standards (Sigma, St. Louis, MO, USA) and the NIST 2007 reference mass spectra (National Institute of Standard and Technology, Gaithersburg, MD, USA). All FAME analyses were based on total ion current chromatograms and/or selected ion monitoring chromatograms.

The finely homogenized spleens (45–60 mg) from each lamb were hydrolyzed according to our previous published method [33 (link)]. Nonadecanoic acid (C19:0) was added to each processed spleen. Next, mild acid- and base-catalysed esterefications were used for the synthesis of fatty acid methyl esters (FAME) in analysed spleens. Next, methylated FA in assayed spleens were analysed using capillary gas chromatography and mass spectrometry (GC-MS) [33 (link)]. GC-MS analyses were performed using a Shimadzu GCMS-QP2010 Plus EI, a BPX70 fused silica column (120 m × 0.25 mm i.d. × 0.25 mm film thickness), and a mass detector (Model 5973 N). FA (as FAME) identification in spleens was validated using the electron impact ionization spectra and compared to the retention times of FAME standards as well as the reference mass spectra library (National Institute of Standard and Technology NIST, 2007). The determination of FAME contents in analytical samples was based on total ion current (TIC mode) chromatograms or/and selected ion monitoring (SIM mode) chromatograms [33 (link)].