Band broadening effects in capillary column recycle gas chromatography with valves

Autor: Wolfgang Bertsch, L. Hathcock, Q. W. Zhang
Rok vydání: 1990
Předmět:
Zdroj: Journal of High Resolution Chromatography. 13:683-688
ISSN: 1521-4168
0935-6304
DOI: 10.1002/jhrc.1240131006
Popis: Sources leading to band broadening and peak distortion have been studied in a capillary column recycle system, based on a commercial microvalve. The ferrule system was a major contributor to band broadening. It was found that the quality of connections is very critical but the internal volume of the valve is not important. The pressure pulses resulting from each switching operation produced some band broadening with substances that had just been transferred through the valve but no adverse effects were noticed when they had travelled some distance into the column. Flow into valve cavities and through tees also produced a drop in efficiency. It is not clear whether this is solely due to problems in column connection or if changes in flow pattern also contribute. The activity of the valve toward polar substances was also assessed. No attempt was made to deactivate valve surfaces. The components of the Grob test mixture were almost unaffected but highly polar and acidic compounds such as nitrophenol showed severe losses. No evidence for catalysis was found.
Databáze: OpenAIRE
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