Sac 5 capillary column

Total cholesterol in thigh meat samples was extracted by direct saponification procedure as described by Adams et al. (1986 (link)) and quantified by gas chromatography on a Hewlett Packard 5890 series II (Avondale, PA) equipped with flame ionization detector and a SAC™-5 capillary column (30 m × 0.25 mm i.d., 0.25 µm film thickness, Supelco, Bellefonte, PA). The carrier gas was helium and the initial and terminal column temperature was programmed at 280 °C. The detector was set at 300 °C.

Hepatic cholesterol was extracted and analyzed according to our previously published procedures [7 (link),32 (link)]. Approximately 500 mg of pulverized liver was spiked with α-cholestane as internal standard and saponified in freshly prepared KOH–methanol at 100°C for 1 h. The non-saponifiable sterol fraction was extracted with petroleum diethyl ether and dried under N₂ gas. For analysis of hepatic fatty acids, approximately 0 · 5 g of pulverized liver was spiked with heptadecanoic acid (C17:0) as internal standard. Total lipids were isolated from liver tissue with a modified Dole mixture (3 hepatane:12 propanol:3 DDH₂O, vol:vol) followed by extraction with heptane: DDH₂O (3:1 vol:vol) [33 (link)]. Fatty acid extracts were methylated with methanolic boron trifluoride (Sigma Aldrich, St. Louis, MO).
Sterol and fatty acid fractions were analyzed using a Shimadzu GC-17A gas chromatograph fitted with a flame ionization detector. A SAC-5 capillary column (30 m × 0 · 25 mm × 0 · 25 mm, Supelco, Bellefonte, CA, USA) was used for cholesterol analyses. Fatty acid methyl esters were separated using a Supelcowax 10 column (30 m × 0 · 25 mm with 0 · 25 m film thickness; Supelco, Bellefonte, PA, USA). Relative hepatic fatty acid content was calculated by using individual FA peak area relative to the total area and expressed as the percentage of total fatty acids.