An LC-MS Method for the Analysis of Some Organic Acids in Tobacco Leaf, Snus, and Wet Snuff

The present study describes the analysis of several organic acids in tobacco and smokeless tobacco products using a liquid chromatography (LC) method with mass spectrometric (MS) detection (LC-MS). Prior to the application of the LC-MS method, a qualitative analysis for the identification of the organic acids in tobacco and oral tobacco products was performed. The qualitative method used direct silylation of the plant material followed by GC-MS separation and detection. For the acids’ quantitation, a novel LC-MS method has been developed and validated. The acids of interest for quantitation were the following: acetic, citric, fumaric, glyceric, lactic, maleic, malic, oxalic, pyroglutamic, pyruvic, quinic, and trihydroxybutanoic. The LC separation was performed on a Synergy 4u Hydro-RP column 250 × 4.6 mm, with an aqueous mobile phase containing 5% methanol and 0.15% formic acid. The LCMS method has the advantage versus LC methods with other detection types (refractive index, UV absorption at low UV range, or conductivity) of being capable of positive identification of the analytes based on their specific ions, and of having significantly better sensitivity. Unfortunately, the LC-MS method was not generating good results for oxalic acid and acetic acid also expected to be present in some samples of tobacco or tobacco products. The study describes the advantages and disadvantages of the LC-MS method for the analysis of organic acids in tobacco and smokeless tobacco products.