Simultaneous quantification of fatty acids in serum with dual derivatization by liquid chromatography‐tandem mass spectrometry

Abstract

Fatty acids have multitudinous biological functions and play a crucial role in many biological processes, but due to poor ionization efficiency and lack of appropriate internal standards, the comprehensive quantification of fatty acids by liquid chromatography‐tandem mass spectrometry is still challenging. In this study, a new, accurate, and reliable method for quantifying 30 fatty acids in serum using dual derivatization was proposed. Indole‐3‐acetic acid hydrazide derivants of fatty acids were used as the internal standard and indole‐3‐carboxylic acid hydrazide derivants of them were used to quantify. The derivatization conditions were systematically optimized and the method validation results showed good linearity with R2 > 0.9942, low detection limit (0.03–0.6 nM), precision (1.6%–9.8% for intra‐day and 4.6%–14.1% for inter‐day), recovery (88.2%–107.2% with relative standard deviation < 10.5%), matrix effect (88.3%–105.2% with the relative standard deviation < 9.9%) and stability (3.4%–13.8% for fatty acids derivants in 24 h at 4°C and 4.2%–13.8% for three freeze‐thaw cycles). Finally, this method was successfully applied to quantify fatty acids in serum samples of Alzheimer's patients. In contrast to the healthy control group, nine fatty acids showed a significant increase in the Alzheimer's disease group.