Improved resins and novel materials and methods for solid phase extraction and high-performance liquid chromatography

Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. By reducing the size of the resin beads and optimizing reaction conditions, resins were produced which had excellent capacities both in the packed-column and the suspension mode. By reducing bead sizes to 1 ;Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. The analysis of drugs in biological fluids usually involves time consuming pretreatment steps for the removal of the drugs from the biological matrix before analysis with HPLC. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment.;A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Small analyte molecules chromatograph normally on these precoated columns. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 ;Finally, membrane-based micro solid-phase extraction (MMSPE) is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. MMSPE consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few...