[Determination of neutral chemical constituents in flue-cured tobacco by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry].

A method was established to analyze neutral chemical constituents in tobacco accurately by comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC x GC-TOFMS). A DB-Petro column (50 m x 200 microm x 0.5 microm) was chosen as the column for the first dimension, and a DB-1701 column (2.3 m x 100 microm x 0.1 microm) was chosen as the column for the second dimension. The modulation period was set at 8 s, and the column pressure was 550 kPa. The initial temperatures of the two columns were set at 80 degrees C and 85 degrees C respectively and then increased with temperature programming. The contents of the neutral chemical constituents in different positions of tobacco leaves, product regions and varieties of tobacco were compared. The results showed that the total contents of the 24 neutral fractions in the middle leaves was the most, then in the upper leaves and the least in the lower leaves. These contents in the flue-cured tobacco produced by Brazil was the highest, followed by Zimbabwe, Yunyan85, Zhongyan101, NC89 and K326. In four kinds of tobacco, the total contents of the 24 neutral fractions in Oriental tobacco was the highest, followed by Burly tobacco, Flue-cured tobacco and Maryland tobacco.