Directed-sorting method for synthesis of bead-based combinatorial libraries of heterogeneous catalysts

Ramanathan Ramnarayanan, Benny C. Chan, Michael A. Salvitti, Thomas E. Mallouk, Falaah M. Falih, Jason Davis, Douglas B. Galloway, Simon R. Bare, Richard R. Willis

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The synthesis and analysis of inorganic material combinatorial libraries by a directed-sorting, split-pool bead method was demonstrated. Directed-sorting, split-pool, metal-loaded libraries were synthesized by adsorbing metal salts (H2PtCl6, SnCl2, CuCl2, and NiCl2) and metal standards (Pt, Cu, Ni in HCl) onto 2-mg porous γ-alumina beads in 96- or 384-well plates. A matrix algorithm for the synthesis of bead libraries treated each bead as a member of a row or column of a given matrix. Computer simulations and manual tracking of the sorting process were used to assess library diversity. The bead compositions were analyzed by energy-dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, electron probe microanalysis, inductively coupled plasma atomic emission spectroscopy, and inductively coupled plasma mass spectroscopy. The metal-loaded beads were analyzed by laser-activated membrane introduction mass spectroscopy (LAMIMS) for catalytic activity using methylcyclohexane dehydrogenation to toluene as a probe reaction. The catalytic activity of individual beads that showed minimal (∼20% of that of Pt on alumina) to high conversion could be determined semiquantitatively by LAMIMS. This method, therefore, provides an alternative to screening using microreactors for reactors that employ catalysts in the form of beads. The directed-sorting method offers the potential for synthesis of focused libraries of inorganic materials through relatively simple benchtop split-pool chemistry.

Original languageEnglish (US)
Pages (from-to)199-212
Number of pages14
JournalJournal of Combinatorial Chemistry
Issue number2
StatePublished - Mar 2006

All Science Journal Classification (ASJC) codes

  • Chemistry(all)


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