Simultaneous Identification and Quantification of Triacyglycerol Species in Human Plasma by Flow-Injection Electrospray Ionization Tandem Mass Spectrometry

Abstract

The analysis of triacylglycerol (TG) species is of interest in diseases that are associated with hypertriglycidemia. The individual composition of TGs seems to be of special interest in the development of atherosclerosis or diabetes type II. Enzymatic methods based on saponification and glycerol analysis are not suited for the TG fatty acid distribution. The aim of the study was to develop a rapid method for a molecular species fingerprinting of TGs. Protein precipitation of 5 µL human plasma was carried out with toluene/methanol (1:1 v/v). Tandem mass spectrometric detection (mass range m/z 700–1,000) was performed by combination of nine neutral loss scans (14:0, 15:0, 16:0, 16:1, 18:0, 18:1, 18:2, 18:3, and 20:4) after flow-injection analysis for 2 min. Deuterated internal standards had been used for quantification. In human EDTA-plasma the detection limit was 3.3 µg/mL and the lower limit of quantification was 11.1 µg/mL. Linearity was proved for TG concentrations up to 100 µg/mL for each TG species. Nineteen TG molecular species were determined with an intra-day coefficient of variation of 15.0–20.9 % (n = 9), and an inter-day coefficient of variation of 17.3–36.6 % (n = 9). Recovery of TG 50:0 using the equivalent internal standard was 97.0 %. Nineteen TG molecular species can be analyzed in 2 min from human plasma or serum by the novel tandem mass spectrometric approach. In subsequent studies, the distribution of plasma TG molecular species can be analyzed under high-throughput conditions in healthy and diseased individuals.