Abstract:
A method for determination of 13 alkaline aromatic compounds in cigar tobacco leaves by gas chromatography-nitrogen chemiluminescence detector/mass spectrometry with headspace-programmable temperature vaporizing (HS-PTV-GC-NCD/MS) was proposed, and 39 alkaline aromatic compounds were identified, by matching with the mass spectrometry library of the National Institute of Standards and Technology (NIST) in the United States. Cigar tobacco leaves were dried at 40 ℃ for 10 h, ground, and passed through a 80 mesh (0.178 mm) sieve. 0.5 g of the sieved tobacco powder sample was taken and placed in a 15 mL-centrifuge tube. 5 mL of saturated sodium chloride solution containing 5% (mass fraction) sodium hydroxide and 20 μL of 20.0 mg·L
−1 ethanolamine internal standard solution were added. The solution was extracted by shaking at 25 ℃ for 0.5 h, and centrifuged at a rotational speed of 4 500 r·min
−1 for 10 min. The supernatant was passed through a 0.45 μm water phase filter membrane, and 2 mL of the filtrate was placed in a 20 mL-headspace flask. Targets in the solution was separated on a DB-WAX chromatographic column according to the column heating program, and NCD was used for quantitative analysis. As shown by the results, linear relationships between the ratios of the corresponding NCD peak area to the internal standard NCD peak area and mass concentrations of 13 alkaline aromatic compounds were found in definite ranges, with detection limits (3S/N) in the range of 0.60-2.99 μg·kg
−1. Test for recovery was made by the standard addition method, giving results in the range of 72.0%-103%, with RSDs (
n=5) of the determined values of intra-day and inter-day less than 10%. This method was used for the analysis of cigar tobacco leaf samples from different origins, and 13 alkaline aromatic compounds were all detected, with detection amounts in the range of 0.9-5 050.4 μg·kg
−1.