SAMPLE PURIFICATION FOR THE ANALYSIS OF CAFFEINE IN TOBACCO BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A commonly used additive to tobacco products is cocoa. A sensitive and selective method was developed to measure caffeine, a marker for coco a, in tobacco by using gas chromatography-mass spectrometry (GC-MS). T obacco components usually produce high background signals in GC-MS ana lysis. Therefore, a series of extraction steps were designed to effect ively purify the tobacco extracts. The analytical recovery of caffeine was 100% when [trimethyl-C-13(3)]caffeine was used as an isotope-dilu tion reference. A linear calibration curve was generated with caffeine concentration ranging from 0.01 to 20 mu g/ml. The detection limit of caffeine was 0.02 mu g/ml in the final solution. This method was appl ied to several commercial tobacco products, of which the corresponding caffeine levels varied from below the detection limit to 125 mu g/g. (C) 1998 Elsevier Science B.V. All rights reserved.