Improved Analytical Method for Determination of Cholesterol-Oxidation Products in Meat and Animal Fat by QuEChERS Coupled with Gas Chromatography-Mass Spectrometry

Cholesterol is widely present in animal fats and meat products and can undergo oxidation to form cholesterol oxidation products (COPs) during heating. The objective of this study was to develop a QuEChERS method for the determination of COPs in edible animal fats and meat products via gas chromatography-mass spectrometry in which the required solvent volume and extraction time were reduced. By employing a DB-5MS capillary column (30 m X 0.25 mm i.d., 0.25 mu m film thickness) and a temperature-programming method, seven COPs, cholesterol, and the internal standard 5 alpha-cholestane could be separated within 19 min. The limits of detection and limits of quantitation based on the COP standards ranged from 0.16 to 180 ng/mL and from 0.32 to 400 ng/mL, respectively, and the recoveries ranged from 89.1 to 107.6% for boiled pork and from 80.5 to 105.6% for lard. The intraday variabilities for boiled pork and lard ranged from 2.27 to 6.87% and from 1.52 to 9.78%, respectively, whereas the interday variabilities ranged from 1.81 to 7.89% and from 3.57 to 9.26%, respectively. Among the various meat samples, fish showed the highest level of COPs (31.84 mu g/g). For the edible fats, the COP contents in tallow (22.79-60.15 mu g/g) were much higher than those in lard (0.152-2.55 mu g/g) and butter (0.526-1.36 mu g/g). Collectively, this method can be applied to determine COPs in cholesterol-containing foodstuffs.