METHODS AND MATERIALS FOR SOLID-PHASE EXTRACTION

Solid-phase extraction (SPE) with porous solid particles goes back to the early 1970s. However, SPE has become more popular recently due to the availability of more efficient particles and the need to replace l iquid extraction procedures that require the use of large quantities o f organic solvents. Chemical introduction of acetyl or hydroxymethyl g roups into polymeric resins improves the efficiency of SPE by providin g better surface contact with aqueous samples. Lightly sulfonated resi ns display excellent hydrophilicity and improved extraction efficienci es of polar organic compounds over underivatized resins. It is shown t hat the degree of sulfonation has a major effect on retention of such compounds. Sulfonated resins can also be used for group separation of neutral and basic organic compounds. The advantages of performing SPE with resin-loaded membranes is discussed.