提出了离子交换色谱法分离测定茶叶中F-、Cl-、Br-、NO-3、H2PO-4和SO2-4 6种无机阴离子含量的方法.茶叶样品中6种阴离子用水在95 ℃超声萃取20 min后,经IonPac AS11-HC阴离子分离柱,AG11-HC阴离子保护柱,以氢氧化钾为淋洗液,浓度从15 mmol·L-1到30 mmol·L-1进行梯度淋洗.F-、Cl-和SO2-4的峰面积与其质量浓度在0.01~150.0 mg·L-1范围内,H2PO-4、NO-3和Br-在0.05~150.0 mg·L-1范围内呈线性关系.6种离子的检出限(3S/N)均小于0.03 mg·L-1.该方法用于茶叶样品中F-、Cl-、Br-、NO-3、H2PO-4和SO2-4的测定,加标回收率在90.9%~100.0%之间,测定值的相对标准偏差(n=5)小于3.5%.

Ion chromatography was applied to the determination of 6 inorganic anions F-,Cl-,Br-,NO-3,H2PO-4 and SO2-4 in tea.The 6 anions in the sample were extracted ultrasonically with water for 20 min,at 95 ℃.The extract was then passed through the IonPac AS11-HC anion-exchange column with AG11-HC protective column.Gradient elution was used to desorb the anions from the column by KOH solution with its concentration varied from 15 mmol·L-1 to 30 mmol·L-1.Linear relationships between values of peak area and mass concentration of F-,Cl-,SO2-4 were obtained in the range of 0.01-150 mg·L-1,and those of the H2PO-4,NO-3,Br- were obtained in the range of 0.05-150 mg·L-1.Detection limits (3/N) of 6 inorganic anions were less than 0.03 mg·L-1.The proposed method was used in the determination of 6 inorganic anions in tea sample,values of recovery found by standard addition method were in the range of 90.9%-100.0%,with values of RSD′s (n=5) less than 3.5%.