Large-volume injection gas chromatography-vacuum ultraviolet spectroscopy for the qualitative and quantitative analysis of fatty acids in blood plasma

Abstract

Qualitative and quantitative determination of fatty acids in plasma is of extreme importance as these are indicators of metabolic diseases. In this work, a sensitive and rugged method for detecting and quantifying fatty acids (as fatty acid methyl ester derivatives, FAMEs) in blood plasma was developed. The use of large-volume injection (LVI) gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) for analysis of fatty acids in blood plasma allowed the injection of higher sample volumes to accommodate sufficient analyte on-column for necessary detection ranges with a run time of 45 min. Calibration curves exhibited consistent linearity and reproducibility and were used along with internal standards for the quantification of 11 saturated and 21 unsaturated fatty acids. Intra-day and inter-day (n = 6) CVs had an average of 5 and 6%, respectively, and recoveries an average of 105%. The concentrations of EPA, DHA, and AA, as well as the omega-3 index and omega-6/omega-3 ratio, were calculated and compared with clinically actionable measurement ranges. Due to the use of LVI, the more volatile analyte (C8:0) was lost and therefore impossible to quantify. The volatility cutoff was determined to be the C10:0 analyte with a molecular weight of 186.295 g/mol.