INSTRUMENTATION FOR COMPREHENSIVE 2-DIMENSIONAL CAPILLARY SUPERCRITICAL FLUID-GAS CHROMATOGRAPHY

A two-dimensional supercritical fluid-gas chromatography system was co nstructed and evaluated. A 50-mum i.d. capillary column coated with a 50 % cyanopropyl polysilixane stationary phase was used as the first-d imensional column. Group-type separations of polycyclic aromatic hydro carbons, based on the number of aromatic rings, were achieved using th is column under SFC conditions. A 25-mum i.d. liquid crystal column wa s used as the second-dimensional column under GC conditions. The efflu ent from the first column (SFC) was received continuously by the secon d column (GC) through a thermal desorption modulator. The thermal deso rption modulator (prepared at the head of the second column) generated a series of concentration pulses from the first column effluent. Thes e concentration pulses served as injections to the second column, and were developed into a corresponding series of high-speed chromatograms . Group-type sample bands from the first column were separated into in dividual components on the second column. All sample substances passed through both columns to generate two sets of retention data, which co uld be used for more accurate compound identification,