Preparation of long packed capillary columns using carbon dioxide slurries

✍ Scribed by Abdul Malik; Wenbao Li; Milton L. Lee

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 758 KB
• Volume: 5
• Category: Article
• ISSN: 1040-7685
• DOI: 10.1002/mcs.1220050409

✦ Synopsis

Abstract

A new, reproducible method is described for the preparation of highly efficient fused silica packed capillary columns using pressure programmed liquid or supercritical carbon dioxide to carry the packing material into the capillary. The method allows facile preparation of long, uniformly packed capillary columns capable of producing over 240,000 theoretical plates in SFC. Columns of up to 10 meters in length were prepared using LC packing materials of different chemical nature and particle size. The new method does not require a separate step for preparing the slurry, and it is free from the drawbacks inherent in conventional slurry‐packing methods. The lower viscosity and surface tension of carbon dioxide compared to conventional slurry‐forming liquids, as well as the use of ultrasonic vibration and pressure programming in the packing process, provide favorable conditions for achieving packing uniformity over greater column lengths than is achievable by other packing techniques. Proper restrictors and appropriate decompression rates during the use of these columns in SFC were found to be very important in achieving optimum column performance. In comparison to the use of open tubular columns, higher effciencies, greater sample capacities, and faster analysis speeds can be obtained. These advantageous features make the newly developed columns suitable for trace analysis, separation of very complex mixtures, and analysis of difficult‐to‐separate solutes.