Determination of Inorganic anions and organic acids in tobacco using Ion chromatography

A method was established for the determination of Cl-、SO42-、PO43-、NO2-、NO3-、malic acid and citric acid in tobacco.The content of NO2-was low in tobacco,and couldn't be analyzed by conductivity detector.Therefore,these five inorganic anions and two organic acids in tobacco were analyzed by ion chromatography/conductivity detector/ultraviolet detector,and NO2-and NO3-were detected by the ultraviolet detector.The chromatographic instrument used was a Dionex ICS-2000 ion chromatograph.The columns used were a Dionex IonPac AS11-HC analytical column(250 mm×4 mm I.D.) and a Dionex IonPac AG11-HC guard column(50 mm×4 mm I.D.).An anions self-regenerating suppressor(ASRS) current from Dionex(Sunnyvale,CA,USA) was used to reduce the conductivity of the eluent.The chromatographic oven was operated at 30 oC,and a Dionex conductivity detector was used at 35 oC.The calibration curves showed good linearity with correlation coefficients of 0.9991~0.9999.The detection limits ranged from 0.001 to 0.02 mg/L,and the recoveries of the method were in the range of 93.7% to 100.8 %.The relative standard deviations(n=5) ranged from 0.3% to 2.1%.The results showed good sensitivity,simplicity and high feasibility.The method was suitable for the determination of Cl-、SO42-、PO43-、NO2-、NO3-、malic acid and citric acid in tobacco.