Novel approach to fast determination of cholesterol oxidation products in Cypriot foodstuffs using ultra-performance liquid chromatography-tandem mass spectrometry.

This paper reports the development and validation of a new method based on ultra-performance LC coupled to MS/MS for the simultaneous determination of four cholesterol oxidation products (COPs) in foodstuffs in only 4.1 min. The COPs were detected by ESI in positive-ion mode with multiple reaction monitoring, and the mass spectrometric conditions were optimized in order to increase sensitivity. The developed method was validated in terms of linearity, precision, LODs, and LOQs. Recoveries of the extraction process ranged from 86 to 98.5% when the samples were fortified at 100, 500, and 1500 ng/mL. The applicability of the method was confirmed by analyzing different food samples. Considering the paucity of data regarding the content of COPs in Cypriot foods, particular attention was devoted, for the first time, to the determination of the profile of the main COPs in widely consumed, traditional Cypriot foodstuffs (halloumi cheese, hiromeri, snails, etc.).

Sample preparation: a critical step in the analysis of cholesterol oxidation products.

In recent years, cholesterol oxidation products (COPs) have drawn scientific interest, particularly due to their implications on human health. A big number of these compounds have been demonstrated to be cytotoxic, mutagenic, and carcinogenic. The main source of COPs is through diet, and particularly from the consumption of cholesterol-rich foods. This raises questions about the safety of consumers, and it suggests the necessity for the development of a sensitive and a reliable analytical method in order to identify and quantify these components in food samples. Sample preparation is a necessary step in the analysis of COPs in order to eliminate interferences and increase sensitivity. Numerous publications have, over the years, reported the use of different methods for the extraction and purification of COPs. However, no method has, so far, been established as a routine method for the analysis of COPs in foods. Therefore, it was considered important to overview different sample preparation procedures and evaluate the different preparative parameters, such as time of saponification, the type of organic solvents for fat extraction, the stationary phase in solid phase extraction, etc., according to recovery, precision and simplicity.

Qualitative and quantitative determination of COPs in Cypriot meat samples using HPLC determination of the most effective sample preparation procedure.

This research work describes the development of a fast high-performance liquid chromatography method for the simultaneous determination of five important cholesterol oxidation products (COPs). The influence of various experimental parameters, such as the composition of the mobile phase, the flow rate and the column temperature, were investigated. Baseline separation was achieved by using acetonitrile-methanol-water-isopropanol (67:27:5:1) as a mobile phase with a 10°C column temperature. The developed method demonstrated good linearity and high reproducibility, with relative standard deviation values below 1.26% for all the COPs that were examined. The method was then applied, for the first time, to Cypriot smoked-meat products (lountza and hiromeri). The presence of COPs in these products suggests that the preparation of the meat products, and particularly the smoking process, possibly favors the oxidation of cholesterol. Finally, three different sample preparation procedures were evaluated and the optimum procedure was determined based on recovery, precision and simplicity.