微波辅助衍生化-气相色谱法测定烟草中非挥发性有机酸

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

在气相色谱法测定烟草中非挥发性有机酸中,提出了用硫酸-甲醇(1+7)混合溶液作衍生试剂,在微波炉中于选定的条件下对所测定的有机酸进行衍生化。经酯化的溶液用二氯甲烷萃取,萃取液蒸缩至2mL,分取1μL进样作气相色谱分析。测定中采用AC 20毛细管柱及火焰离子化(FID)检测器并用戊二酸作内标,对7种非挥发性有机酸用标准加入法作回收及精密度试验,测得回收率在97.5%～103.3%之间,相对标准偏差(n=5)在1.6%～4.4%之间。用所提出的方法测定了烤烟、卷烟及白肋烟样品中非挥发性有机酸,测定结果与文献方法的结果相符。

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 H_2SO_4 and CH_3OH（1＋7）in a microoven under optimized working condition.The esterized solution was extracted with CH_2Cl_2,and the extract was evaporated to a volume of 2 mL.OneμL 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 nonvolatile organic acids were tested by standanl 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.