膜处理-离子色谱法测定碳酸钡中的杂质阴离子

Determination of anion impurities in barium carbonate by ion chromatography with membrane treatment

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^-、SO^(2-)_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≥0.999 6。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--,SO-（2-）_4and NO--_3）in barium carbonate. The cation exchange membrane was applied in providing H＋in hydrochloric acid to dissolve barium carbonate and to prevent anions dissolving into the solution from hydrochloric acid. After pretreatment by acid dissolution and membrane treatment,the sample was diluted for 100 times and filtrated 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 detectionwere 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-,SO2-4and NO-3anions were between 84. 0% and 106. 2%. This method can determine the three inorganic anions（F-,SO2-4and NO-3）in barium carbonate fast and accurately. It is suitable for the simultaneous separation and detection of trace inorganic anions in insoluble products.