ABSTRACT
Over the past decade solid-phase extraction (SPE) techniques have largely replaced liquid/liquid methods as the preferred technique to extract drugs from biological fluids prior to quantitative analysis. As the name suggests, extraction is performed by absorbing the analyte(s) from the matrix onto a solid support (sorbent). SPE methods typically have four main steps: a priming step to ensure conditions are optimal for retention of the analyte, a retention step where the matrix is applied to the cartridge and the analyte is retained, a rinsing step where potential interferences are eluted while the compound of interest remains bound to the sorbent, and an elution step where the purified analyte is collected for analysis (Figure 2.1).
