Core concepts and milestones in the development of solid-phase extraction

Abstract The evolution of materials, apparatus, and techniques for the solid-phase extraction of gas and liquid samples is described and their virtues placed in a modern context of the requirement for streamlined, efficient, low-cost, and automated sample preparation methods. For gas-solid extraction methods include cartridge- and needle-based packed beds with thermal desorption to recover target compounds and typically gas chromatography for analysis. For liquid-solid extraction cartridge-based, membrane-based (disk), and thin-film based sorbents are used with a wide range of inorganic oxide, low-specificity, and high-specificity sorbents. Second generation formats include microextraction by packed sorbent, solid-phase microextraction, in-tube solid-phase extraction, stir bar sorptive extraction, coated magnetic nanoparticles, nanofibers, and monoliths. Low-specificity sorbent chemistries include silica-based chemically bonded sorbents, macroreticular porous polymers, carbon (activated, graphitized, and carbon nanotubes). High-specificity sorbents include mixed-mode, immunosorbents, aptamers, molecularly printed polymers, metal-organic frameworks, and restricted access media. A general theory of sample processing for cartridge and disk devices is presented for the estimation of breakthrough volumes, rinse solvent conditions, and recovery of target compounds by solvent or thermal desorption.