Silica Materials for Chromatography and Extraction – IP 1652

Currently available bonded phasesused in HPLC, UPLC and SPE employ silica particles as the base material. Toincrease the phases applicability and adaptability, the surface of theparticles can further be modified by bonding a wide variety of functional groupsto the surface: non-polar (e.g. C18), polar (e.g. NH2), ionic (e.g.propylsulphonic acid) or mixed-mode (e.g. C8/cation exchange). However, the state-of-the-artapproach to preparing bonded silica particles results in a number of inherentshortcomings. For example, a thin coating of the bonded phase must provide allof the required analyte/sorbent/stationary phase interactions, which imposes arequirement of a high volume of stationary phase loaded into a long column sizeto achieve a large sample breakthrough volume, which is the maximum samplevolume that can be passed through the column without saturating the bed withthe analytes. Often there is an insufficient organic group loading per unitmass of the stationary phase/SPE sorbent to achieve adequate separation orabsorption. Finally, the state-of-the-artphases display a very narrow range of pH stability, typically, at best, havinga robust stationary phase when maintained within a pH range of 2 to 8. FIU inventors have developedsol-gel synthesis of alkyl functionalized (e.g., C4, C8, C12, C18) HPLC, UPLC and SPE sorbents. The synthetic method employs a tetrafunctionalsilane and a trifunctional silane containing a sorbent functionality, forexample, tetraalkoxy silane and an alkyltrialkoxy silane or their equivalentsin presence of either an acid catalyst, an acid catalyst followed by a basecatalyst, or a base catalyst. This method yields a chemically and structurallymore stable highly porous hybrid inorganic-inorganic material. Due to the highporosity and extremely high surface area, the HPLC stationary phase and SPEsorbents offer more analyte-alkyl functional group interactions per unit massof the stationary phases/SPE sorbents, consequently minimizing the requiredmass of the stationary phases/SPE sorbents to achieve target chromatographicseparation and extraction efficiency. Additionally, consumption of organicsolvents in chromatographic separation and sample preparation is significantlyreduced. Anne Laure Schmitt Olivier aschmitt@fiu.edu 305-348-5948