Fractionation of soybean phospholipids by preparative high-performance liquid chromatography with sorbents of various particle size.
Normal-phase high-performance liquid chromatography was used on a preparative scale to seperate phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylcholine (PC) phospholipids from soybean. Separation was achieved using mixtures of three solvents, hexane, methanol and isopropanol. The optimized mobile phase compositions were experimentally determined while operating in a linear gradient mode using 15, 5-20, 25-40, and 40-63 microm preparative particles as well as 4 microm analytical particles. A gradient mobile phase was established on a commmercially available analytical Nova-Pak column such that hexane linearly decreased from 85 to 0 as isopropanol and methanol linearly increased in two gradient steps from 10 to 30 and 5 to 70 respectively. The total run time was 25 min at a flow-rate of 1.5 ml/min. A slight change in mobile phase composition was required to increase the resolution of phospholipids. The 15 microm particle size gave the best separation of the preparative particle sizes examined based on their resolutions between PE and PI and PI and PC. Finally, the retention factors of PE and PC were correlated in terms of mobile phase composition.
Preparative separation of phospholipids from soybean by NP-HPLC
Soybean phospholipids-phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylcholine (PC)-were separated by normal-phase high performance liquid chromatography. The system was operated in a gradient mode. The experimental variables were gradient time and mobile phase composition. The experimental results showed that PE, PI and PC were resolved by three step-change gradient modes which employed ternary systems of hexane/1-propanol/water (58/40/2 and 56/40/4 by vol.%) and methanol/1-propanol/water (80/18/2, by vol.%) for the gradient times of 10, 30 and 76 min, respectively.
Preparation of surfactant multilayer films on solid substrates by deposition from organic solution
Abstract The spreading of organic surfactant solutions on solid surfaces is shown to be a practical and efficient method to prepare homogeneous, substrate-aligned, thin organic films. The characterization of such solution-deposited films of phospholipids by X-ray diffraction, electron microscopy and ellipsometry is described. Under suitable conditions, solution spreading yields multilayer films which are aligned parallel to the substrate surface, adopt a well-defined layer thickness and thus display a single color, and exhibit a low density of morphological defects which are identified by electron microscopy. Conditions favorable to controlled multilayer deposition include the complete wetting of the substrate by the organic solution of surfactant and the minimization of mass flow during spreading and solvent evaporation. The choice of an appropriate spreading solvent was found to be crucial to producing homogeneous films.