Determination of Moisture, 1,2-Propylene Glycol, Glycerol and Nicotine in Tobacco and Tobacco Products by Gas Chromatography with Medium Collision Extraction

The industry standards of determination of moisture, 1,2-propylene glycol, glycerol and nicotine in traditional cigarettes were no longer applicable to new type tobacco products. In order to develop a method suitable for the determination of moisture, 1,2-propylene glycol, glycerol and nicotine in all kinds of tobacco and tobacco products, a method of gas chromatography with medium collision extraction was proposed using a mixture of methanol and triethylamine at volume ratio of 100∶15 containing 6.5 g·L^-1 isopropanol (internal standard of water), 2.5 g·L^-1 1,4-butanediol (internal standard of 1,2-propylene glycol and glycerol) and 4.0 g·L^-1 n-heptadecane (internal standard of nicotine) as extraction solvent. 0.400 0 g of tobacco sample was taken, which did not need to be broken, and placed into a 15 mL-centrifuge tube. And 10 mL of extraction solvent was added. The extraction was carried out under the linear velocity of 4 m·s^-1 for 2 min at room temperature, settling for 3 min. The supernatant was filtered through 0.22 μm organic filter membrane, and then determined by gas chromatography. As shown by the results, the 4 main components in tobacco and tobacco products could be completely extracted in only 2 min by the pretreatment method of medium collision extraction. Linear range of moisture standard curve was within 10.00 g·L^-1, while linear ranges of the standard curves of 1,2-propylene glycol, glycerol and nicotine were within 5.00 g·L^-1, with detection limits (3s) of 0.030-0.35 mg·g^-1. Tests for intra-day precision (n=6) and inter-day precision (n=8) were carried out on the same sample, with RSDs of determined values less than 4.0%. Test for recovery was made by standard addition method, giving results in the range of 95.2%-100%.