烟草中有机酸和无机阴离子的离子色谱法分析及聚类分析研究

Analysis of organic acids and inorganic anions in tobacco by ion chromatography and cluster analysis

建立了超声辅助萃取-离子色谱法测定烟草中5种有机酸和4种无机阴离子的方法。烟草中的草酸主要以钙盐的形式存在,难溶于水,因此采用60mL0.15mol/LHCl萃取测定烟草中总草酸的含量,而烟草中的甲酸、乙酸、苹果酸、水溶性的草酸、柠檬酸、Cl-、NO3-、SO42-、PO43-则采用60mL去离子水在60℃下以60%的功率对烟草样品超声萃取20min,以DionexAS11-HC为分离柱、IonAG11-HC为保护柱、ASRS-ULTRAⅡ为再生抑制器,KOH溶液为流动相,用电导检测器同时测定其含量。结果表明,该方法的线性范围是0.5～800mg/L,相关系数为0.9990～0.9999,相对标准偏差小于4.2%,检测限0.048～0.334mg/L,回收率为90.33%～100.1%。采用此方法测定了23种不同烟样中9种有机酸和阴离子的含量,该方法操作简单、重现性好、灵敏度高,适于批量烟草样品中9种有机酸和无机阴离子的快速准确分析,对于监控卷烟的质量、提高烟草制品安全性具有重要意义。并且以5种有机酸为指标对23种烟样进行聚类分析,结果表明:该方法可用于不用种类烟丝的比较和分类,5种有机酸的含量分布特征能反映不同种类烟丝的特性,对烟丝的分类具有一定的参考价值。

An ultrasonic wave extraction combined with ion chromatography （IC） method for determination of 5 organic acids and 4 inorganic anions in tobacco was developed. Oxalic acids in tobacco mainly existed in the form of calcium salts that were difficult to dissolve in water, so they were extracted by 60 mL 0.15 mol/L HCl. Formic acid, acetic acid, malic acid, water- soluble Oxalic acid, citric acid, Cl^- , NO3^- , SO4^2- and PO4^3- in tobacco were extracted by ultrasonic wave with deionized water at 60℃ for 20 minutes, separated on a Dionex AS11-HC column, with IonPac AG11-HC as guard column and ASRS-ULTRA Ⅱ as regenerative depressor. KOH solution was used as eluent. The analytes were detected by a conductivity detector. It was found that the recoveries of the method were between90.33 % and 100.1%, the relative standard deviation was equal or less than 4.2 %, the correlation coefficients of linear regression equations were from 0. 9990 to 0. 9999, and the detection limits in the range of 0.0480.334 mg/L. The content of 5 organic acids in 23 tobacco samples were determined with this method, and the data were processed with cluster analysis. Results showed that the method can be used in comparison and classification of tobacco of different varieties, and the proportion distribution of 5 organic acids reflected clearly the characteristics of different cut tobaccos, which can be served as a reference in tobacco classification.