Generic method for the extraction of quaternary amines and polybasic drugs from biological fluids using ISOLUTE® HCX-Q mixed-mode SPE
By Biotage
The use of ISOLUTE® HCX mixed-mode sorbents is widely accepted for providing high purity extracts of basic drugs from biological fluids. The dual retention mechanism, provided by non-polar and strong cation exchange functional groups, allows for a rigorous interference elution step resulting in low levels of co-extracted materials, thus minimizing the risk of ion suppression effects in LC-MS applications. This approach is suitable for drugs that can be eluted under basic conditions. However, quaternary amines and polybasic drugs cannot be eluted under these conditions. ISOLUTE® HCX-Q, containing non-polar and weak cation exchange functional groups, was designed to allow elution of these compounds under acidic elution conditions. The ISOLUTE HCX-Q sorbent utilizes a combination of weak cation exchange and C8 non-polar retention mechanisms. The analyte is initially retained by a non-polar (hydrophobic) retention mechanism, which is unaffected by high or variable ionic strength of the sample matrix. The pH control and salt removal at the sample application stage ensures that the polybasic drug or quaternary amine is retained by a robust cation exchange retention mechanism.
Literature number: TN129.V.2
