Mass spectrometric study on the source of error in quantification of free fatty acids

Abstract

Development of an optimized sample preparation method to minimize exogenous free fatty acid (FFA) contaminants is a key process in quantitative analysis of food or lipidomics. Among the saturated or unsaturated FFA, palmitic acid (PA) and stearic acid (SA) are common saturated FFA found as a contaminant. Unfortunately, these two FFAs were most frequently quantified as important target compounds in food analysis. In addition to PA and SA, other FFA contaminants were intermittently detected and identified as exogenous contaminants, which were also mainly targeted in food analysis. The consumables used in the sample preparation step are mainly plasticware and the slip agents employed in the process of making plastics are generally composed of PA and SA. These exogenous contaminants can bring inaccurate quantitative results by overestimating the amount of endogenous FFAs. Here, I conducted a mass spectrometric study to develop a sample preparation method minimizing quantitative errors in the quantification of FFAs. Finally, the extent of influence due to exogenous FFA contaminants on the analysis of actual samples was evaluated using skimmed milk samples where endogenous FFA contained at the trace levels.