GSTek-HPLC-UO9501050-Metal-Unisol-C18-5-Micrometer-100-Angstrom-46-x-10mm-4pk

GS-Tek's unique sol-gel process technology generates a uniform surface that produces a universal column applicable to many HPLC applications. Peak tailing adversely affects chromatographic efficiency and reduces the resulting accuracy and precision of the data. Peak tailing and insufficient retention of polar compounds are among the toughest problems for silica based reversed phase columns. High acidity of the surface silanols, non-uniformity of the surface, and non-uniformity of the bonding process are the three major causes of peak tailing. High purity synthetic silica is typically obtained by hydrolyzing silicic acid esters followed by high temperature sinteration. The sintered silica is further leached with dilute acid to enrich silanol on the surface. The process does not generate a uniform, silanol covered surface. It will create some isolated silanol groups with very strong acidity or some "un-leached islands" during the leaching process. Furthermore, the high temperature procedure may cause formation of micro-crystallization domains on the amorphous silica, further contributing to the nonuniformity of the surface.

Unisol process technology is specifically designed to solve these problems. In our patented Unisol process, gas phase tetramethoxy silane is adsorbed evenly on the silica surface. It is subsequently hydrolyzed by a controlled amount of moisture. A fresh layer of silanols is then formed by a mild heating process. This process produces a surface with lower acidity and high uniformity, which is further bonded with a high purity C18 silane, and then di-functional end-capped. The overall process yields an excellent HPLC stationary phase with a very smooth surface that is friendly to basic compounds (minimal ionic interactions) and polar compounds (provides significantly increased retention).