getting rid of matrix effect
Posted: Thu Aug 20, 2009 9:30 pm
How can we get rid of matrix effect
Go to the Waters.com website and search for the "Oasis Applications Notebook". It is full of examples that can guide you this type of application.
Here is an example for the application (I am not sure what sphinganine is. I assume that it has a long hydrophobic chain and either a quaternary or tertiary amine that will be charged at acidic pH, and no other groups that are charged). If it is a tertiary amine, use Oasis MCX which retains by both hydrophobic interaction and cation exchange. Acidify your sample (plasma or standard) with a strong acid, such as phosphoric acid. Filter and load onto the cartridge. Wash off polar interference with 10% methanol 90% acidified water. Wash off hydrophic interferences with methanol. Then elute with methanol/ammonia. If it does not elute cleanly, you need to play with it by substituting some of the methanol with acetonitrile or THF.
In case I am wrong about the nature of the sphinganine, I need instructions from you about all the different charged groups on it.