Comparison of the Effectiveness and Environmental Impact of Selected Methods for the Determination of Fatty Acids in Milk Samples

Abstract

Determination of the fatty acid profile in milk samples is one of the most important in food analysis. There are many methodologies for FA determination. The conventional procedure for determining the FA composition of milk is isolation of fat or indirect methylation, trans-methylation, extraction of fatty acids, and analysis by gas chromatography. In this study, eight methods based on alkaline methylation were compared for the analysis of fatty acids in cow’s milk. The response factors (RF) for GC analysis using FID were calculated. For most acids, RFs were close to 1, with the exception of short-chain fatty acids (C4:0–C8:0). To facilitate the selection of the method for the determination of fatty acids in milk samples, the methods were assessed using the environmental assessment tools of the analytical procedure: the Analytical Eco-Scale, Green Analytical Procedure Index (GAPI), and Analytical Greenness for Sample Preparation (AGREEprep). The method based on direct milk methylation received the highest scores. Omitting the lipid separation step has an impact on reducing the quantity of used toxic chemicals and reagents, and produces a smaller amount of waste, a much higher throughput, and a reduced cost analysis.

A Comparative Analysis on the Environmental Impact of Selected Methods for Determining the Profile of Fatty Acids in Cheese

“…The oxidation energy leads to ionization, so in these molecules, the oxidized carbon atom is split, and this fragment cannot produce ions and a response in the detector. When this happens, it is necessary to use a response factor relative to each analyte with respect to an internal standard to correct the responses of the detector [ 13 , 18 , 19 ]. The experimental response factors (ERFs), theoretical response factors (TRFs), and error factors (EFs) used here were described in our previous study [ 13 ], and are listed in Table S1 .…”

“…When this happens, it is necessary to use a response factor relative to each analyte with respect to an internal standard to correct the responses of the detector [13,18,19]. The experimental response factors (ERFs), theoretical response factors (TRFs), and error factors (EFs) used here were described in our previous study [13], and are listed in Table S1.…”

“…Several tools are employed in green analytical chemistry to study the environmental performance of an analytical procedure, including the Analytical Eco-Scale tool, the National Environmental Methods Index (NEMI), the Green Analytical Procedure Index (GAPI), the Analytical Greenness (AGREE) tool, and the newer Analytical Greenness Metric for Sample Preparation (AGREEprep) tool. Objective criteria related to analytical performance, environmental impact, sustainability, and economic cost are evaluated by these tools through the definition of penalty points [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. This makes it possible to choose the most environmentally friendly analytical procedure, which is very important nowadays for both ecological and also economic and analytical reasons.…”

Comparative Analysis and Determination of the Fatty Acid Composition of Kazakhstan’s Commercial Vegetable Oils by GC-FID

“…In GC analysis, the identification of FAs is based on changing the FAs to the corresponding fatty acid methyl esters (FAMEs), which have a higher volatility [6,24]. The most commonly used base reagents for rapidly changing FAs into FAMEs are NaOH or KOH in methanol [29,30]. Other methods of methylation used benzyl alcohol, diazomethane in a mixture of ether, trichloride boron and sodium methoxide in methanol [31][32][33][34].…”