Characterization of cigar tobaccos by gas chromatographic/mass spectrometric analysis of nonvolatile organic acids: application to the authentication of Cuban cigars.

Abstract

A reliable method based on gas chromatographic/mass spectrometric (GC/MS) profiling of nonvolatile organic acids is described for the characterization of cigars. The method involves an aqueous extraction of ground tobacco and selective isolation of the acids by simply stirring strong anion exchange (SAX) disks in the aqueous tobacco extract. The acids are then directly silylated on the disk with N-methyl-N-trimethylsilyl-trifluroacetamide (MSTFA) in acetonitrile in an autosampler vial. Elution of the derivatized acids in situ allows the sample to be directly analyzed by GC/MS without further sample handling. Compared to the conventional disk-extraction technique using a vacuum manifold, this method is much less labor intensive, and is desirable for multiple sample analysis. Nicotinic acid, succinic acid, glyceric acid, malic acid, pyroglutamic acid, threonic acid, citric acid, uracil, and an unidentified acid were reproducibly quantified in tobacco samples. Principal component analysis (PCA) of the acid profiles of the filler tobaccos of 18 Cuban cigars and 31 non-Cuban cigars shows separation of the two groups, indicating that the acid profiles are potentially useful in the authentication of Cuban cigars.