The gas chromatographic determination of binary diffusion coefficients : II. An experimental evaluation

✍ Scribed by C.E. Cloete; T.W. Smuts; K. De Clerk

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 727 KB
• Volume: 120
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(01)98993-9

✦ Synopsis

The izhromatographic determination of binary diffusion coefficients by means of the peak arrest method has been evaluated experimentally. Experimental deviations are generally in the range OS-1.0%.

INTRODUCITON

This paper describes an experimental assessment of the potential of the peak arrest (PA) method for the chromatographic determination of binary gaseous diffusion coefiicients. It is based on a theoretical analysis outlined in a previous paperI, to which the reader is referred for definitions of the symbols used. The primary concern is with the development of a reliable experimental method. This is a long-term project of which the present study is regarded as the first stage. It should therefore be seen as a design study of the relative importance of the basic elements of the method within the limits imposed by existing facilities. No attempt was made to extend the method to the Limits of current technology. Most of the results are nevertheless within the 1% precision level, which compares favourably with the best determinations to date. The construction of a refined model for routine measurements at the 0.1 0k level appears to be possible.

~STRUMENTATION

The theoretical analysis' has shown that it is irratioual to aim at a precision much below 1 ok if peak measurements are carried out manually. Recognition of this limitation wZl conse&rently be the prime consideration in selecting the various components required for the analysis, The main items are the column, inlet, detector, recckder and the devices used for measuring the gas flow, peak width, time, temperature and pressure. These items are considered separately below. I We thank -The South African Council for Scientific and Industrial Research, Sh& S.A., The Nederhtmis-&id Afrikaanse Veieniging and the lndustrid Development &rp&ation of So&h Af?ica for &an&l assistance.