Abstract: In order to quickly detect and analyze the content of free fatty acids in tobacco leaves,Ultraperformance convergence chromatography mass spectrometry（UPC²/MS） was established for the rapid analysis of 5 kinds of fatty acids, palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, in 8 kinds of tobacco leaves, and identification of 32 kinds of free fatty acids. The results showed that HSS C₁₈ chromatographic column （SB 1.8 μm, 2.1 mm×150 mm） was used as the analytical column, CO₂ and 0.1% formic acid solution of methanol was used as the mobile phase to gradient elution by ACQUITY UPC² chromatographic system and Xevo TQS mass spectrometer. The 5 kinds of fatty acids had a good linear relationship within the range of 2.2~72.2 ng/mL （r>0.999）; the detection limit （S/N≥3） was 0.06~0.13 ng/mL; the quantitative limit （S/N≥10） was 0.19~0.41 ng/mL; the relative standard deviation （RSD） of precision was 5.2%~8.0%; the relative standard deviation （RSD） of stability was 4.3%~7.5%; the relative standard deviation （RSD） of repeatability test was 3.0%~6.7%; the average recovery rate was 95.8%~97.2% at different addition levels. The contents of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid in 8 tobacco leaves ranged from 0.12 mg/g to 1.21 mg/g. The method is rapid, sensitive, selective and simple in sample pretreatment without derivation. It is applicable for the determination of free fatty acids in tobacco leaves.

Key words: UPC²/MS, tobacco leaves, free fatty acids