Solid-Phase Extraction

In a solid-phase extraction of a liquid sample, we pass the sample through a cartridge containing a solid adsorbent. A typical separation is illustrated here. Before adding the sample, the solid phase cartridge is rinsed with suitable solution. Next, as shown in (a), the sample is pulled through the cartridge, with the analytes and matrix interferents retained by a liquid–solid extraction. Washing the cartridge (b) with a suitable solvent removes the interferents, but leaves behind the analytes. Finally, as shown in (c), we elute the analytes using a suitable extracting solvent.