Master of Science
Presented is a solid phase extraction (SPE) sorbent having a removable "stationary phase." This removable phase that consists of alkyltrimethylammonium surfactant is initially immobilized onto hydrophilic strong cation exchange resin. The surfactant chain through hydrophobic interactions extracts hydrophobic analytes in the same manner as conventional bonded alkyl moieties on silica based non-polar sorbents. For the extraction of very hydrophobic species with conventional sorbents, solvents used for analyte elution are generally toxic and not directly instrument compatible. The chosen solvent must be strong enough to efficiently break hydrophobic interactions between the analyte and sorbent. Using a removable "stationary phase," hydrophobic interactions need not be broken between the analyte and the sorbent. In the presented approach, the surfactant ("stationary phase") is removed via ion exchange with exchange ions in very mild aqueous based and instrument compatible solutions. The analyte, being associated with the surfactant, is also removed in the process. Very efficient elutions of hydrophobic analytes are a direct benefit of having a removable "stationary phase." Rinse solution parameters explored include exchange cation type and concentration, and alcohol type and concentration. The extraction of three polyaromatic hydrocarbons, naphthalene, pyrene and benzo(ghi)perylene, is investigated using this sorbent material. A silica based strong cation exchange resin (SCX-2) having a sulfopropyl group is explored and compared with the commercially available silica based extraction sorbent.
Oakes, Tony, "Silica Based Solid Phase Extraction Sorbent with a Removable Alkyltrimethylammonium Surfactant Phase" (2003). Masters Theses & Specialist Projects. Paper 559.