FFAP PLOT column

Despite the usual preference in GC for the application of more polar stationary phases for the resolution of polar species, the former may be applied usefully for nonpolar separations. Figure 4 illustrates the resolution of the alkane-alkene pairs of the hydrocarbon fraction of shale oil (sample as in Figure 2), on a FFAP PLOT column (100ft). FFAP is Carbowax 20M terminated with terephthalic acid residues. This column selectively retains olefins and enables base-line resolution of the alkane-alkene pairs. The only disadvantage of this phase is its temperature limitation of ca. 250°C. Identification of the numbered peaks in Figure 4 was achieved by interfaced MS (components are listed in Table 1). 

Figure 4, Gas chromatogram of nonpolar fraction of TOSCO 11 (Green River) shale oil on a 100 X, 03 in. i,d. FFAP PLOT column. Substrate Chromosorb R6470-1 temperature program 40°-225°C at 4" C/min,...

This PLOT separation allowed vapor-phase IR and mass spectral determinations to be made. Figure 7 shows a typical IR spectrum obtained from Peak X in the above FFAP chromatogram. The spectrum corresponds to a 6-sec scan with computer background correction and normalization. The spectral features correspond well with an alkyl phenolic structure and a comparison spectrum is shown in Figure 8 for 2,4-dimethylphenol eluted from the FFAP column under identical condi-... 

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