Relationship between trans-column eddy diffusion and retention in liquid chromatography: theory and experimental evidence.
Experimental results demonstrate that trans-column eddy diffusion depends on the retention of compounds. The combination of elution profiles recorded in different points of the exit column cross-section and of the height equivalent to a theoretical plate (HETP) of small molecules clearly show a strong link between retention and column performance in liquid chromatography. These results validate a new model of trans-column eddy diffusion in packed columns. The contribution to the column HETP of the trans-column eddy diffusion term decreases with increasing retention factor from k'=0 to k'=3 above which it becomes negligible. The best column performance in RPLC is observed for the most retained compounds. This is due to the combination of the lack of a residual trans-column eddy diffusion contribution and the vanishing contribution of the instrument to band broadening.
Gritti
Fabrice
F
Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
Guiochon
Georges
G
D016227:Benzoquinones; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D004058:Diffusion; D000432:Methanol; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry; D015203:Reproducibility of Results; D014498:Uracil
D016227:Benzoquinones; D009930:Organic Chemicals; C004532:quinone; D014498:Uracil; D000432:Methanol