Organic Acids. Malic, Citric, Acetic, Oxalic, Pectic and Ulmic.
Other Organic Substances. Nicotianin, Green and Yellow Resin, Wax and Fat, Nitrogenous Substances and Cellulose.
The substances which differentiate tobacco from other plants and form its chief characteristics are Nicotianin, Nicotine and Malic Acid.
The percentage in which the important substances exist in tobacco is given below:
| Nicotine | From | 1 | to | 9% | |
| Malic and Citric Acids | From | 10 | to | 14% | |
| Oxalic Acid | From | 1 | to | 2% | |
| Resins, Oils and Fats | From | 4 | to | 6% | |
| Pectic Acid | About | 5% | |||
| Cellulose | From | 7 | to | 8% | |
| Albumenoids | About | 25% | |||
| Ash | From | 12 | to | 30% | |
When tobacco is burned, chemical changes occur; the organic and other compounds are decomposed. The volatile matters pass off in the smoke if the combustion is complete, and the mineral ash remains. In ordinary pipe or other tobacco smoking, however, the combustion is not complete and many decomposition products remain with the mineral ash.
In tobacco smoke the following can usually be found: Furfurol, Marsh Gas, Hydrogen Sulphide, Hydrogen Cyanide, Organic Acids, Phenols, Empyreumatic Oils, Pyridine, Picoline Series and possibly some Nicotine.
The ash left after complete combustion is important, as much of the smoking qualities of the tobacco depends on its constituents. An average sample gives the following analysis (in 100 parts):
Average mineral contents of tobacco ash
| Potash | About | 27% | |
| Soda | About | 3% | |
| Lime | About | 40% | |
| Magnesia | About | 9% | |
| Sodium Chloride | About | 9% | |
| Sulphuric Acid | About | 3% | |
| Silica | About | 5% | |
| Lime Phosphate | About | 4% |