922 (2001) 37–50 Journal of Chromatography A, www.elsevier.com / locate / chroma Liquid crystalline polymers as stationary phases IV. Chemical bonding and immobilization of the polymer on silica characterization by solid-state nuclear magnetic resonance spectroscopy a,b a,b c c a, b * ´ F. Gritti , I. Terrien , S. Menu , E.J. Dufourc , G. Felix , M.-F. Achard , b F. Hardouin a ´ E.N.S.C.P .B., Universite Bordeaux I-Lab. d’ Analyse Chimique par Reconaissance Moleculaire, 16 Avenue Pey-Berland, F-33607 Pessac Talence, France b ´ C.R.P .P .-CNRS, Universite Bordeaux I- Avenue du Dr Schweitzer 33600 Pessac, France c ´ ´ I.E.C.B., Ecole Polytechnique / Universite Bordeaux I / Universite Bordeaux II / CNRS- Avenue Pey-Berland, F-33402 Talence, France Received 18 December 2000; received in revised form 18 April 2001; accepted 19 April 2001 Abstract Chemical bonding reaction and immobilization through low energy radiation (heating) have been investigated to fix a side-chain liquid crystalline polymer (SC-LCP) on silica particles in order to use the resulting modified silica in normal-phase HPLC. Highly stable chromatographic stationary phases are observed under excellent polymer solvent flow conditions (THF) for both methods and better column efficiencies are also exhibited towards PAHs’ separation compared to the classical coated stationary phase. The characterization of these new stationary phases and the rationale for improved 13 29 column stability have been investigated by solid state C and Si CP/ MAS NMR spectroscopy. It is clearly shown that the chemical bonding is achieved by the classical hydrosilylation reaction between PHMS chains and vinyl modified silica. The bonded polymer is likely a copolymer than a homopolymer. The immobilization of the SC-LCP by heating results in the breaking of Si–O–Si bonds of the polysiloxane chain after the attack of the silica surface silanols. Applications to fullerenes and carotenes separation of these bonded stationary phases are compared to the separation power of a classical monomeric C stationary phase in NP-HPLC as n-hexane–toluene or methyl-tertiobutyl ether–methanol mixtures.  2001 Elsevier 18 Science B.V. All rights reserved. Keywords: Stationary phases, LC; Chemical bonding; Immobilization; Liquid crystalline polymers 1. Introduction their applications from reversed-phase to normal- phase conditions. By this way it will be easier to use Continuing our work on new stationary phases appropriate mobile phase condition, compatible with based upon side-on fixed liquid crystalline polymer the solute solubility to obtain good separations. Up in RP-HPLC [1–5], it has been decided to enlarge to now the use of our based liquid crystalline polymer stationary phases were only limited to *Tel.: 133-556-846-561; fax: 133-557-962-239. reversed mobile phase conditions (like MeOH–H O 2 0021-9673 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0021-9673(01)00886-X