Two-dimensional Capillary GC For The Analysis Of Aromatics In Gasoline, Aviation Kerosene And Diesel Fuel By Normalization Method

The aromatics in gasoline, aviation kerosene and diesel was separated well by capillary GC using column switching-backflushing technique and quantitatively analyzed by normalization method.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 an a apolar analytical column and were separated according to their boiling points. Since the earlier eluting components from the pre-column, and the aromatics and heavier saturates from the analytical column are all directed to the same FID detector through a "T" piece, a factor corrected normalization method can be applied for quantitative analysis.The resistance of the resistor after the pre-column is designed 7 times higher than that of analytical column, resulting in 6.4 times higher carrier gas flow rate after back-flushing. The chromatographic bands are compressed, enhancing the sensitivity 3 times more for aromatics and heavier saturates.The aromatics, from benzene to C9 in the gasoline, from benzene to Cn in the aviation kerosene, were separated well and quantitatively analyzed. The switching time window is more than +18 seconds. And the RSD of reproducibility of the analysis is ≤4.0%.