A chromatogram of the aldehydes in sunflower oil from the 5% phenylpolydimethyl siloxane column using an electron capture detector is shown in Figure 43. Helium was used as the carrier gas at 35.5 ml/min. and an argon-methane make up gas at 60 ml/min. for the electron capture detector and hydrogen at 30 ml/min. for the nitrogen phosphorous detector. It is seen from the chromatogram that adequate resolution is obtained between the individual aldehydes and the reported detection limits ranged from 1x10-14 and 1x10-13 mol/ml using the electron capture detector.

1. Methanal	6. Butanal	11. Trans-Hexanal
2. Ethanal	7. Isopentanal	12. Heptanal
3. Acetone	8. Crotanaldehyde	13. Octanal
4. Propanol	9. Pentanal	14. Nonanal
5, Acrolein	10. Hexanal	15. Decanal

Courtesy of the Journal of Chromatography

Figure 43. Chromatogram of Carbonyl Compounds from Sunflower Seed Oil Monitored as Pentafluorophenylhydrazine Derivatives

The results obtained from the analysis of urine are shown in figure 44. Urine samples were taken every 2 hrs from ten fasted men 20-25 years old after each had drunk 1.8 l of beer over an hour period. 5 ml of urine was derivatized at room temperature with one ml of pentofluoro phenylhydrazine solution (0.22 M in 0.1 M hydrochloric acid solution- The pentofluorophenylhydrazine derivatives were isolated using an SPE cartridge containing an octadecyl bonded packing. The derivatives were recovered with 5 ml of hexane which was evaporated to 1 ml at room temperature in a stream of nitrogen. The same columns and operating conditions were used and it is seen that again adequate resolution is achieved. Recovery using SPE was estimated to be 81-98% whereas that obtained by solvent extraction ranged only from 61=79%.