Mixed mode SPE of pollutants in water on mechanically blended silica-based bonded phases .1. Influence of the preparation method

Cartridges for Solid-Phase Extraction operating in mixed mode were filled with two phases: C-18 bonded silica and propylsulfonic acid bonded silica, mechanically blended according to two methods: one dry, the other by suspension in acetonitrile. They were compared with cartridges containing the individual phases, and with a mixed phase having two functionalities bonded onto a common silica particle. The percent recoveries of neutral, basic and acidic environmental pollutants and their reproducibilities were determined by HPLC. After evaluation of the optimum eluent volume, the blended phase prepared without solvent and very rapidly, was overall very promising in terms of retention, reproducibility and composition potential.