hydrophillic and hydrophobic amino acids

The most common classes of phospholipids are the glycerophospholipids (which are composed primarily of glycerophosphocholines), lysophospholipids and sphingolipids (Figure 1) which make up 70% (glycerophospholipids), 10% (lysophospholipids) and between 10 - 20% (sphingolipids) of total phospholipids.

Phospholipids are a major component of cell membranes are thus ubiquitously found throughout the human body. This results in them being amphipathic - the polar phosphate head giving the hydrophilic property with the tails responsible for hydrophobic properties. Phospholipids are a class of lipids which contains both a phosphate head and up to two fatty acid derived tails. However, this preparation technique does not remove phospholipids from the sample which can cause a number of complications and hinder results. It is a quick and easy method to prepare the solution and prevent the proteins from affecting downstream applications when injected onto the chromatography instrument. This process involves adding an organic solvent, ‘salting out’ or by adjusting the pH of the plasma solution which then causes the proteins to crash out of solution. The simplest preparation method is to use protein precipitation. In order for LC-MS to be used for drug development analysis, it requires sample clean-up to remove interferences from plasma before injection onto the system to obtain reliable and consistent results.Ĭlean-up of plasma can be performed before analysis in several different ways. For drug development in DMPK, different compounds are screened and properties assessed, this is usually by Liquid Chromatography - Mass Spectrometry (LC-MS). This application note explores the use of the Microlute® PLR 96 well plate to show it is possible to achieve highly reproducible recoveries alongside removal of phospholipids to eliminate the problems they cause with analysis.īlood plasma is an important matrix in drug metabolism and pharmacokinetic (DMPK) studies where it is used in large quantities for bioanalysis work. Ion suppression leads to other issues during chromatographic runs such as irreproducible results, loss of signal intensity and poor quantitation. However, the phospholipids present in plasma can cause a range of issues with analysis such as higher backpressures, an increased need for instrument maintenance and matrix effects in the form of ion suppression when using ESI-MS detection.

Plasma is a common matrix used in bioanalysis.

Hydrophillic and hydrophobic amino acids