A Column By-Pass System and Its Application in High-Temperature Size-Exclusion Chromatography

✍ Scribed by Nicolai Aust; Stephen O'Donohue; Amjad Jade Yakhoul; Najib Zash

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 117 KB
• Volume: 291
• Category: Article
• ISSN: 1438-7492
• DOI: 10.1002/mame.200500363

✦ Synopsis

Abstract

Summary: A new by‐pass system for chromatographic columns is presented and its efficiency in detecting disturbances during the chromatographic run is demonstrated. The system, designed for HT SEC, is based on a ten‐port valve and allows by‐passing without the need of time and work consuming replacement of the column by a capillary and vice versa. In addition, the construction guarantees a continuous low flow of eluent through the column also when by‐passed, which helps substantially to prolong lifetime of the SEC column at high temperature. Combining the chromatograph with “absolute” detectors, e.g. a light‐scattering detector or viscometer, erroneous molecular parameters caused by polymer degradation due to wrong column selection or run conditions can be easily detected by comparing measurements with and without the column. Therefore, using the chromatograph in by‐pass mode, it can be regarded as an additional, independent apparatus, delivering e.g. the $\overline M _{\rm w}$ or [η] of a polymer sample. The by‐pass system enables a reliable calibration of concentration detectors in chromatography. With the aid of a detector calibration curve, even a small amount of polymer adsorbed in the SEC column can be detected by comparing the peak area derived from the concentration detector to the one to be expected from the calibration data. The column by‐pass could find application except for HT SEC also in other fields of HPLC.

Scheme of the by‐pass system.

magnified imageScheme of the by‐pass system.