离子色谱法测定拜尔法铝酸钠溶液中有机酸和无机阴离子

Determination of organic acids and inorganic anions in Bayer process sodium aluminate solution by ion chromatography

建立了拜尔法铝酸钠溶液中多种有机酸和无机阴离子的离子色谱分析方法。样品经活化好的OnGuard H型固相萃取柱处理后,可有效去除其中大量的金属离子基体干扰,采用离子色谱梯度淋洗和抑制电导检测。结果表明:甲酸、乙酸、丙酸、草酸、丁二酸和戊二酸等有机酸和F-,Cl-,SO24-等无机阴离子能在33 min内同时分离测定。该方法线性关系良好(r=0.994 7-0.998 9),所有被测成分的检出限均小于0.036μg/mL。测定结果的相对标准偏差都在3.2%以下,样品加标回收率在94%-103%之间。

A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer sodium aluminate liquors was developed by gradient ion chromatography with suppressed conductivity detection. The organic acids （formic acid, acetic acid, propionic acid, oxalic acid, succinic acid, glu- taric acid） and inorganic anions （fluorion, chlorion, sulfate readical） were separated and determined within 33 min.The sample was pretreated with solid phase extraction, which could effectively removed a large number of metallic ions from the sodium aluminate solution. The separation of six organic acids and three inorganic anions is achieved on an lonPac AS11-HC column with KOH as the eluent, no interference is found in the presence of fluorate,chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range（ r = 0. 994 7 - 0. 998 9）. The relative standard deviations of the peak area of analytes are less than or equal to 3.2 %. The detection limits for analytes are no more than 0. 036 μg/mL and the recoveries of the added standards are between 94 % - 103 %.