Dynamically-modified silica--an alternative to reversed-phase high-performance liquid chromatography on chemically bonded phases.
An alternative to the well known reversed-phase separations on chemically-bonded phases has been developed. The approach is based on a dynamic modification of bare silica with long chain quaternary ammonium ions. The influence of the concentration and type of the quaternary ammonium ion, the pH value and the ionic strength of the eluent on the selectivity towards test solutes has been investigated. The large number of parameters that can be varied in the system offers numerous possibilities by which the desired selectivity can be attained. Once established, a high degree of reproducibility of the selectivity between solutes is obtained even when using different brands of silica; this is in contrast to the situation when using chemically-bonded phases, such as, for example, different brands of octadecylsilyl-bonded silica materials.
Hansen
S H
SH
Royal Danish School of Pharmacy, Department of Organic Chemistry, 2 Universitetsparken, DK-2100 Copenhagen, Denmark.
Helboe
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P
Thomsen
M
M