建立了一种膜处理-离子交换色谱测定碳酸钡中痕量杂质阴离子（ F-、SO2-4和 NO-3）的方法。碳酸钡是一种难溶于水的固体，因此选用酸对其进行溶解。为了减少酸根离子的影响，利用阳离子膜只能通过阳离子而阻碍阴离子交换的特点，用质量分数为7％的盐酸溶解阳离子交换膜内的碳酸钡样品，稀释100倍，过0.22μm滤膜，进样分析，进样体积为25μL。经流速为1 mL／min 的20 mmol／L KOH 淋洗液淋洗，目标离子经过 Ion Pac AG11-HC保护柱（50 mm×4 mm）和 Ion Pac AS11-HC阴离子交换色谱柱（250 mm×4 mm）进行分离，最后由抑制电导进行检测。在优化的色谱条件下，该方法在0.01~5.00 mg／L范围内线性关系良好，相关系数 R2≥0.9996。相对标准偏差（ RSD）为1.87％~2.19％，检出限（ S／N=3）为1.37~9.45μg／L。将该方法应用于实际样品的检测中，得到样品的加标回收率为84.0％~106.2％。该方法实现了固体碳酸钡中杂质阴离子含量的测定，为水不溶性固体物质中的离子检测提供了依据，具有较好的应用前景。
An ion chromatographic( IC)method with membrane treatment was developed for the simultaneous determination of anions(F-,SO2-4 and NO-3)in barium carbonate. The cation exchange membrane was applied in providing H+ in hydrochloric acid to dissolve barium car-bonate and to prevent anions dissolving into the solution from hydrochloric acid. After pre-treat-ment by acid dissolution and membrane treatment,the sample was diluted for 100 times and fil-trated by a 0. 22 μm membrane,then analyzed by IC using 20 mmol/L KOH as the eluent. The target anions were separated by an Ion Pac AG11-HC(50 mm×4 mm)and an Ion Pac AS11-HC ( 250 mm × 4 mm ) ion-exchange columns and detected by suppressed conductivity detection with 50 mA current. Under the optimized separation conditions,the calibration curves showed good linearity( R2≥0. 999 6)in the range of 0. 01-5. 00 mg/L. The limits of detection were in the range of 1. 37-9. 45 μg/L with the relative standard deviations( RSDs)of 1. 87%-2. 19%. The recoveries of F-,SO2-4 and NO-3 anions were between 84. 0% and 106. 2%. This method can determine the three inorganic anions( F-,SO 2-4 and NO-3 )in barium carbonate fast and accu-rately. It is suitable for the simultaneous separation and detection of trace inorganic anions in insoluble products.
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