Development of Gas Chromatography/Mass Spectrometry for the Determination of Essential Fatty Acids in Food Supplemental Oil Products

Abstract

A gas chromatography/ mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, α-and γ-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-d 35 , 13C 18 -linoleic acid, and 13C 18 -α-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

Quantitative analyses of essential fatty acids in cereals and green vegetables by isotope dilution-gas chromatography/mass spectrometry

“…We have used the HP-88 column which shows a good separation for the FAMEs in our previous studies. ( Lee et al, 2019a;An et al, 2013) The total ion chromatograms (TICs) using the HP-88 column were obtained under optimized extraction and GC conditions described in the experimental section. Figure 1 shows the TICs of the FAMEs extracted from rice and wheat flours, as well as spinach and Kimchi cabbage powders.…”

The Importance of Reference Materials and Method Validation for Advancing Research on the Health Effects of Dietary Supplements and Other Natural Products

“…Ahn et al from the Korea Research Institute of Standards and Science used SRM 3274 to validate their ID-GC-MS candidate reference method for the determination of three essential fatty acids (linoleic, α- and γ-linolenic acid) in supplement oil products ( 93 ). The results for the three fatty acids in the borage, evening primrose, and flax oil were in excellent agreement with the SRM certified values.…”