Synthesis and characterization of long chain alkyl stationary phases on a silica hydride surface

C-22 and C-30 alkyl chains were attached to a silica hydride surface by a h ydrosilation reaction. In each case both moieties were successfully bonded by either metal complex catalysis or free radical initiation. Carbon analys is, DRIFT spectra and C-13 CP-MAS NMR spectra confirm the bonding of the ol efin to silica hydride. Conditions for maximum coverage were determined by a simplex procedure. Chromatographic evaluation of these long chain bonded phases was accomplished by separations of several types of mixtures: alkyl substituted benzenes, polycyclic aromatic hydrocarbons; carotenoids, tocoph erols; tricyclic antidepressants; and peptides. The C-30 column proved sign ificantly better for separating the carotenoid and antidepressant mixtures and somewhat better for the peptide sample.