Development and use of carbon adsorbents in high-performance liquid-solid chromatography : I. Carbon-coated silica particles

Abstract

The technique for coating silica particles with a layer of pyrocarbon is described. The conditions of preparation are important as they determine both the chromatographic performance and the degree of agglomeration of particles during coating. The effect of the coating was studied in terms of both efficiency and retention data. For the silica studied (Spherosil XOB 75), moderate amounts of pyrocarbon (less than 15%) gave the best results; greater degrees of coating give a large decrease in efficiency with increasing retention, while smaller degrees of coating give very small retentions and polar adsorbents. Some simple separations are shown to illustrate the analytical characteristics of these adsorbents.