title: Custom made C18 columns for the hydrophobic chromatography of cephalosporin C derivatives.
abstract: "Hydrophobic chromatography", which is a variation of reverse phase chromatography, is applicable to the analysis of cephalosporin C derivatives, especially in fermentation broths. Unfortunately, there are no commercial C18 columns which are entirely suitable for this class of compounds. For this reason C18 columns were prepared by an in-situ bonding technique and were optimally designed for cephalosporin C derivatives. Mono-, di- and trifunctional octadecyl bonding agents were used with 10 microns silica of both 60 A and 100 A pore diameter. The best results were obtained with the difunctional agent, methyloctadecyldichlorosilane, and 100 A silica. "Endcapping" of residual silanol groups with a trimethylsilylation agent was optional, since good results were obtained with both a plain C18 column and one that was "endcapped".
mesh_terms: D002511:Cephalosporins / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D012822:Silicon Dioxide
chemical_list: D002511:Cephalosporins; C025071:deacetylcephalosporin C; C025578:deacetoxycephalosporin C; C025163:cephalosporin C; D012822:Silicon Dioxide