Capillary gas chromatographic column switching-backflushing technique for the analysis of aromatics in aviation kerosene by normalization method

the aromatics in aviation kerosene was separated and analyzed by capillary gas chromatography using column switching-backflushing technique. the aromatics having carbon number of n are retained after n-cn+3 on the ffap pre-column, and were cut and back flushed after the elution of n-cn+3, onto a nonpolar analytical column and were separated according to their boiling points. since the early eluting components from. the pre-column, and the aromatics and heavier saturates from the analytical column are all directed to the same flame ionization detector through a "t" piece, a factor corrected normalization method can be applied for quantitation. the resistance of the resistor after the pre-column is designed 6 times higher than that of analytical column, resulting in 5.4 times higher carrier gas flow rate after backflushing. the chromatographic bands are compressed, enhancing the sensitivity 2 times more for aromatics and heavier saturates. two aviation kerosene samples were analyzed and the switching time window is more than +/- 18 s. the error of reproducibility of the analysis is less than or equal to4.0%.