1. Isobutane	12. 3–Methylhexane	23. o–Xylene
2. n–Butane	13. 2,3,4–Trimethylpentane	24. 1–Methyl–3–ethylbenzene
3. Isopentane	14. n–Heptane	25. 1,3,6–Trimethylbenzene
4. n–Pentane	15. 2,5–Dimethylhexane	26. 1,2,4–trimethylbenzene
5. 2,3–Dimethylbutane	16. 2,4–Dimethylhexane	27. 1,2,3–Trimethylbenzene
6. 2–Methylpentane	17. 2,3,4–Trimethylpentane	28 Naphthalene
7. 3–Methylpentane	18. Toluene	29. 2–Methylnaphthalene
8. n–Hexane	19. 2,3–Dimethylhexane	30. 1–Methylnaphthalene
9. 2,4–Dimethylpentane	20. Ethylbenzene	31. Dimethylnaphthalene
10. Benzene	21. m–Xylene
11. 2–Methylhexane	22. p–Xylene

Courtesy of Supelco Inc.

Figure 35 The Separation of Gasoline

The FID detector provided the necessary wide quantitative dynamic range. The column temperature was held at 35°C for 15 min. to effect the separation of the low boiling, low molecular weight hydrocarbons, the temperature was then increased to 200°C at 2°C/min. and finally held at 200°C for 5 min. to ensure the complete elution of the higher boiling components.

An excellent separation is obtained giving clearly separated peaks for the marker compounds that are of importance in fuel evaluation. Nevertheless, due to the complexity of the sample, exceedingly high efficiencies were necessary and so, the analysis time was about 100 min. Long analysis times are directly related to the use of long columns The complete analysis was carried out using only 0.1 ml of gasoline with a split of 100:1 at 250°C (ca 1 mg) confirming the remarkable sensitivity of the FID for general analysis.