Sample preparation for LC-MS / MS using magnetic particles

摘要

A method for purifying a compound from a liquid biological sample complex, said compound is selected from the group consisting of itraconazole, sirolimus, tacrolimus, everolimus and mycophenolic acid, said method including the steps of (a) contacting the sample with an amount of magnetic particles functionalized with hydrophobic surface that is functionalized with an alkyl group C18, and the compound is able to interact directly with the hydrophobic, or capable surface to participate in hydrophobic interactions after addition of reagents ion pairing, and wherein the ratio particles / sample is equal to or greater than 1, 25 mg / ml, (b) incubating the sample and the particles, thereby adsorbing the compound on the hydrophobic surface, (c) separating the particles by applying magnetic fields and subtracting the liquid, (d) washing the particles optionally, (e) eluting the compound from the partic ssrooms, characterized so that in step (e) itraconazole eluted with a mixture selected from the group including (i) a mixture of 1-9 parts by volume of acetonitrile and 1 part by volume of formic acid (0, 1% [v / v]) and (ii) a mixture of 9 parts by volume of methanol and 1 part by volume of formic acid (0, 1% [v / v]), and in step (e) the sirolimus, tacrolimus, everolimus or mycophenolic acid eluted with a mixture of 9 parts by volume of methanol and 1 part by volume of water. In a particular embodiment of the invention the sample is selected from the group consisting of serum, plasma, whole blood and hemolyzed blood.