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 liquid extraction procedures that require the use of large quantities of organic solvents. Chemical introduction of acetyl or hydroxymethyl groups into polymeric resins improves the efficiency of SPE by providing better surface contact with aqueous samples. Lightly sulfonated resins display excellent hydrophilicity and improved extraction efficiencies of polar organic compounds over underivatized resins. It is shown that 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.