SCF-TP on-line  

2018, N3, pp. 67-76

M.O. Kostenko, O.I. Pokrovskiy, O.O. Parenago, V.V. Lunin

Comparison of Hold-up Time Determination Methods in Supercritical Fluid Chromatography

Three most common methods for measuring chromatographic hold-up time in supercritical fluid chromatography are tested. It is shown that at low concentrations of polar cosolvents in the mobile phase, the use of the simplest system peak method leads to highly inaccurate results. With an increase in the percentage of co-solvent to 1015 %, this method can be used for rough estimation of hold-up time values, especially for non-polar stationary phases. The use of nitric oxide(I) as a nonretentive hold-up time marker, on the contrary, is well suited only in the case of pure carbon dioxide as a mobile phase. The static method theoretically can give very precise values of hold-up time, but it requires the knowledge of mobile phase velocity profile along the whole chromatograph tract.

Key words: hold-up time, supercritical fluid chromatography, system peak, nonretentive compound, static method


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