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Service life of counter-current chromatography coils
- Source :
- Journal of Chromatography A. 1151:103-107
- Publication Year :
- 2007
- Publisher :
- Elsevier BV, 2007.
-
Abstract
- A multilayer coil of PTFE tubing, which failed after being used each workday for about 3 years in a type J centrifuge, was examined. Two types of defects were found. One, called crazes, occurs throughout the coil and does not leak initially, but may eventually lead to a short, axially oriented slit. Another, called indentations, is seen primarily in the innermost and other nearby layers. They are elongated, about 5 mm, indentations, usually on the central side of the tubing. These eventually crack and leak. PTFE tubing is permeable to air and hexane and expands by more than 1% when immersed in hexane, heptane or chloroform for a few days. It is suggested that the crazes result from exposure of the somewhat flexible tubing to the undulating centripetal force field in the coil-planet centrifuge, especially when further softened by solvent absorption. The indentations may result from carriage of the excess tubing length, created by solvent absorption, from the coil periphery to the coil center by the centripetal force field, which continuously travels from the peripheral tail to the central head of the coil. A 1% increase in coil length creates 74 cm of excess tubing in the 160-ml coils examined in this study. It is suggested that fluorinated ethylene propylene (FEP) tubing, especially when etched on the outside, may provide more stable CCC coils, since its expansion when exposed to organic solvents is 0.1 or less than that of PTFE.
- Subjects :
- Leak
Centrifuge
Chromatography
Chemistry
Organic Chemistry
General Medicine
Biochemistry
Heptanes
Analytical Chemistry
chemistry.chemical_compound
Countercurrent chromatography
Fluorinated ethylene propylene
Electromagnetic coil
Service life
Hexanes
Head (vessel)
Chloroform
Absorption (chemistry)
Countercurrent Distribution
Subjects
Details
- ISSN :
- 00219673
- Volume :
- 1151
- Database :
- OpenAIRE
- Journal :
- Journal of Chromatography A
- Accession number :
- edsair.doi.dedup.....6d2934e154e667132436541cd6dbe01b