CAPCELL PAK C18 MG III, Polymer-coated C18 Stationary Phase, Designed for High-Sensitivity analyses in LC–MS

Kazuko Haseyama, Yoshihisa Hiroe, and Yasuo Igarashi, SHISEIDO Co., Ltd.

The SHISEIDO CAPCELL PAK C₁₈ MGIII is an HPLC column packed with a silicone polymer-coated phase, providing excellent peak profiles for basic compounds under acidic conditions, and generating ultimately minimized column bleeding in LC–MS.

As speed and sensitivity in mass spectrometers have remarkably improved, chromatographic separations can be a major quality-determining factor in LC–MS in some cases. Often discussed are peak profiles of basic compounds under acidic mobile phases preferably used for electrospray ionization (ESI), reproducibility of retention for basic compounds under acidic conditions, and column bleeding influencing ionization efficiencies of analytes.

Figure 1

Since its first release in the 1990s, several different types of the CAPCELL PAK columns have been developed. The CAPCELL PAK C₁₈ MGIII is the latest model designed to overcome the three issues above and has been developed by refining the original polymer-coating technology.

Figure 2

Experimental

CAPCELL PAK C₁₈ MG III phase was synthesized, at first, by placing high-purity silica in contact with vapor of 1,3,5,7-tetramethylcyclo-tetrasiloxane molecules to form a reactive monolayer of the silicone polymer, and thereafter, modifying

the polymer-coated silica with 1-octadecene through hydrosilation to form C18 groups. Instruments used here were a semi-microcolumn HPLC system, NANOSPACE SI-2 (Shiseido) connected to AccuTOF, a time-of-flight mass spectrometer (JEOL, Tokyo, Japan). Other MS conditions were described in

the figures.

Results

Malachite green is a basic compound, which often induces peak tailing due to residual silanol groups on silica-based stationary phases. As shown in Figure 1, CAPCELL PAK C₁₈ MGIII showed excellent peak shape, suggesting that the silica's undesirable secondary effect had been eliminated by the polymer-coating technology. In addition, three synthetic lots showed good reproducibility and little variation in chromatogram.

Figure 2 shows how column bleed influences the sensitivity in LC–MS. Column bleed not only messes up a total ion chromatogram, but may lower an intensity of the analyte itself. CAPCELL PAK C₁₈ MG III showed the lowest level of column bleed among other commercially available C18 phases.

Conclusion

The polymer-coating technology resulted in an excellent C18 phase showing good peak shapes for basic compounds under acidic conditions, and also, a minimized column bleed, which seems advantageous in its applications in LC–MS.

SHISEIDO Frontier Science Business Division

1-1-16 Higashi-shimbashi, Minato-ku,

Tokyo 105-0021, Japan

Email: Chrom1@po.shiseido.co.jp

www.shiseido.co.jp/HPLC