This technical note describes the extraction of acidic drugs from biological fluids using ISOLUTE® HAX mixed-mode SPE products.
Sample preparation techniques such as protein precipitation, supported liquid extraction or non-polar SPE may not be selective enough to give extracts of sufficient purity for low level analysis. In these cases, the selective mixed-mode approach to the extraction of acidic drugs is a suitable alternative, giving very high purity extracts with minimal levels of co-extracted material.
ISOLUTE HAX mixed-mode SPE sorbent is based on a combination of strong anion exchange and non-polar chemistries. Acidic drugs are retained by two primary retention mechanisms (see Figure 1). This allows a rigorous interference elution regime to be used to elute interferences retained by either non-polar or anion exchange interactions alone. Only analytes with both non-polar and acidic characteristics are extracted using the ISOLUTE HAX sorbent, providing an extremely pure final extract.
Literature number: TN127.V.2