Ionic liquid based microextraction of targeted lipids from serum using UPLC-MS/MS with a chemometric approach: a pilot study

Abstract

In the present study an ionic liquid based vortex assisted surfactant-enhanced emulsification microextraction (IL-VASEME) method followed by Plackett–Burman Design (PBD) and Central Composite Design (CCD) using liquid chromatography-electrospray mass spectrometry (LC-ESI-MS/MS) have been used for the determination of fatty acids, triglycerides and phospholipids in serum samples. The study helped in the detection of these lipid classes in a single run within 5 min. The extraction method parameters were statistically optimized by a design of experiment (DOE) approach to reduce the extraction time. The ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (C₄MIMPF₆) was used as an extraction solvent, while the surfactant, Triton X-100 was used as an emulsifying agent. The statistical method, PBD screened the most significant factors such as ionic liquid volume, surfactant strength and pH for optimizing the conditions for the separation of lipids. The screened factor values were based on the CCD design, which optimized the conditions like 45 μL of ionic liquid, 7.5 pH and 1.25% of surfactant strength for extraction of lipids. The limit of detection (LOD) and limit of quantification (LOQ) were 0.012–0.034 ng mL⁻¹ and 0.046–0.114 ng mL⁻¹ respectively. The recovery of lipids was in the range of 90.9–114%. The intraday and interday precision in the serum sample ranged between 1.42–4.48% and 3.75–10.8% respectively. This study reveals that the proposed IL-VASEME coupled with liquid chromatography tandem mass spectrometry method is more sensitive for the extraction and determination of lipids in a single step as compared to traditional methods.