Determination of amino acids in tobacco flavors by liquid chromatography tandem mass spectrometry

A method for determining 18 amino acids in tobacco flavors by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Using L-norvaline (Nva) as an internal standard, the sample was extracted by 10% methanol-water solution (HCl concentration of 0.1 mol/L), and the extract was directly analyzed by LC-MS/MS after filtering with a 0.22 μm aqueous phase filtration membrane. The results showed that: the linear correlation coefficients of 18 amino acids were above 0.9990 in the range of 0.1-10 μmol/L, and the recoveries of 3 standard addition levels ranged from 85.4% to 110.0% with the relative standard deviation (RSD) of 1.3%-4.9%. The limits of detection (LODs) and the limits of quantification (LOQs) of the method were 0.00005-0.1 μmol/L (S/N=3) and 0.0002-0.3 μmol/L (S/N=10), respectively. This method is accurate, sensitive and suitable for determining the amino acids in tobacco flavors.