GC Determination of Non-volatile Organic Acids in Tobacco with Microwave Assisted Derivatization

In the gas chromatographic determination of non-volatile ogranic acids in tobacco, a modification of the derivatization of the organic acid was made by reacting with a mixture of H2SO4 and CH3OH (1+7) in a microoven under optimized working condition. The esterized solution was extracted with CH2Cl2, and the extract was evaporated to a volume of 2 mL. One μL aliquot was taken for GC analysis. AC 20 capillary column and FID detector were used in the analysis, and pentanedioic acid was used as internal standard. Recovery and precision for 7 non-volatile organic acids were tested by standard addition method, values of recovery and RSD′s (n=5) found were ranged from 97.5% to 103.3% and from 1.6% to 4.4% respectively. The proposed method was used in the determination of non-volatile organic acids in samples of flue-cured tobacco, cigarettes and burley tobacco, giving results in consistency with the results obtained by the method reported in literature.