固相萃取-石墨炉原子吸收法光谱分析铝合金中痕量铍的研究

建立了固相萃取-石墨炉原子吸收光谱法测定铝合金中铍的方法。利用偶氮砷酸类试剂7-(2′-胂酸基-5′-羧酸)苯偶氮-8-羟基喹啉-5-磺酸(H2L)与Be2+形成螯合物,该螯合物可用C18固相萃取柱富集,而Al3+则不被保留。采用石墨炉原子吸收光谱法(GF-AAS)测定C18柱洗脱液中的Be2+的螯合物,从而实现铝合金中铍的分离检测。最佳实验条件为:采用pH=3.0的5%H2L水溶液螯合Be2+,水相上柱,用2mL体积比为50%的甲醇/水溶液作为洗脱液。结果表明:经过C18柱固相萃取可以去除Al3+的干扰,Be2+的测定范围为0.05～16μg/L,检出限为0.025μg/L,加标回收率为92%～108%。应用该法于铝合金标样中铍的测定,结果与认定值相符。

Determination of Beryllium in Aluminum Alloy Sample by Solid Phase Extraction-Graphite Furnace-Atomic Absorption Spectrometry

A new method for the determination of beryllium in aluminum alloy sample was established by pre-extraction with 7-(2′-Arsenazo acid-5′-carboxylic acid) phenylazo-8-hydroxyl-quinoline-5-sulfonic acid(H_2L) and determination with graphite furnace-atomic absorption spectrometry. H_2L was chosen as the extraction agent to separate Al~(3+) and Be~(2+). C18-solid phase extraction was employed for the separation and enrichment of beryllium in alloy samples. The optimum experimental conditions were as following, 5.0% H_2L(pH=3.0), flow rate of 1.5 mL/min. elution with 2.0 mL 50% (V/V) methanol/water solution. The linear range of the method was 0.05～16 μg/L,the recovery was between 92%～108% and the detection limit was 0.025 μg/L. The method has been applied to the determination of beryllium in certified reference material and the results obtained were in good agreement with certified values, giving the RSD of 2.3%(n=5).