In the anal. of complex mixtures by supercrit. fluid chromatog. d. programming is usually needed. The retention characteristics under linear d. programming was investigated in this paper. Based on the capillary column model, the retention value and height equivalent to a theor. plate equation have been derived as follows. The derived equation of retention value has been verified by experimental results using capillary and micro-packed columns at different operating conditions.)

Key words: OPEN TUBULAR COLUMN, MICRO-PACKED COLUMN