Simultaneous assessment of lipid classes and bile acids in human intestinal fluid by solid-phase extraction and HPLC methods

• Main Authors: Eva Persson, Lars Löfgren, Göran Hansson, Bertil Abrahamsson, Hans Lennernäs, Ralf Nilsson
• Format: Article
• Language: English
• Published: Elsevier 2007-01-01
• Series: Journal of Lipid Research
• Subjects: solid-phase extraction; high-performance liquid chromatography; evaporative light scattering; neutral lipids; phospholipids
• Online Access: http://www.sciencedirect.com/science/article/pii/S0022227520436569

The purpose of the study reported here was to develop a method for the determination of lipid classes in intestinal fluids, including bile acids (BAs). A solid-phase extraction (SPE) method using C18 and silica columns for the separation of BAs, phospholipids (PLs), and neutral lipids (NLs), including free fatty acids, has been developed and validated. Fed-state small intestinal fluid collected from humans was treated with orlistat to inhibit lipolysis and mixed with acetic acid and methanol before SPE to maximize lipid recoveries. BAs, PLs, and NLs were isolated using lipophilic and polar solvents to promote elution from the SPE columns. The different lipid classes were subsequently analyzed using three separately optimized HPLC methods with evaporative light-scattering detectors. High recoveries (>90%) of all lipids evaluated were observed, with low coefficients of variation (<5%). The HPLC methods developed were highly reproducible and allowed baseline separation of nearly all lipid classes investigated. In conclusion, these methods provide a means of lipid class analysis of NLs, PLs, and BAs in human fed-state small intestinal fluid, with potential use in other fluids from the intestinal tract and animals.