APPLICATION NOTES

HPLC

Bidentate C8™ column for more Hydrophobic compounds. Analytes

Shorter analysis time. Method Conditions Column:

Cogent Bidentate C8 (Octyl)

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 75 mm Mobile phase: 70:30 methanol/DI water Flow rate: 1.0 mL/minute Injection Volume: 5 µL Sample: Universal LC Test Mix 1. benzene 4. isopropyl benzene 2. toluene 5. tert.-butylbenzene 3. ethylbenzene 6. anthracene Detection: UV 254 nm

Discussion Cogent Bidentate C18(ODS)

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.

TABLE 1 Column

k1’ tert.-butylbenzene

4.19 A. Cogent C8 B. Cogent BDC18 19.98

Cat. No. 40008-75P 40018-75P

k2’ anthracene

4.57 31.49

For more information visit www.MTC-USA.com a= k2’/k1’

1.10 1.58

Description Cogent Bidentate C8 HPLC Column. 4µm, 100Å. 75mm x 4.6mm ID. Cogent Bidentate C18 HPLC Column. 4µm, 100Å. 75mm x 4.6mm ID. APP A44

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