Shorter Analysis Time

For separations requiring a less hydrophobic Stationary Phase, Cogent C8 can be used successfully as demonstrated in the Chromatograms. The Retention on the C8 Column is lower when compared with a C18 Column under the same Mobile Phase conditions, but since the Efficiency is excellent the separation goals can be achieved in a shorter time.

The C8 phase is suited for more hydrophobic proteins and peptides and large nonpolar organic compounds. For increased Retention higher percentages of Water in the Mobile Phase can be used. The diminished hydrophobicity is shown in Table 1.

1. Benzene
2. Toluene
3. Ethylbenzene
4. Isopropyl Benzene
5. Tert-Butylbenzene
6. Anthracene

Method Conditions
A: Cogent Bidentate C8™ (Octyl), 4µm, 100Å
B: Cogent Bidentate C18™ (ODS), 4µm, 100Å
Catalog No.:
A: 40008-75P
B: 40018-7.5P
Dimensions: 4.6 x 75mm
Mobile Phase: 70% Methanol / 30% DI Water
Injection vol.: 5µL
Flow rate: 1mL / minute
Detection: UV @ 254nm
Sample: Universal LC Test Mix

Table 1

Column k1′ k2′ a=k2’/k1′
A. Cogent C8 4.19 4.57 1.10
B. Cogent C18 19.98 31.49 1.58



No 44 Hydrophobic Compounds Analyzed with HPLC pdf 0.2 Mb Download File