石墨炉原子吸收测定间接空冷机组循环水中的痕量铝

Determination of trace aluminum in indirect air cooling unit circulating water by graphite furnace atomic absorption spectrophotometry

采用石墨炉原子吸收测定SCAL型间接空冷机组循环水中的痕量铝,从石墨炉工作参数、基体改进剂、试剂空白、水样前处理等方面进行了实验条件优选。实验结果表明:石墨炉灰化温度、原子化温度分别为700℃和2 700℃,不加基体改进剂条件下,铝离子标液质量浓度在0~20μg/L范围内标准曲线线性相关系数可达到0.999 8,相对标准偏差小于10%,检测下限为0.5μg/L。采用水样酸化静置1 h后直接测定并与标准加热消解法测定值进行了对比,相对误差小于5.0%,空白值小于0.5μg/L,有效解决了加热消解法空白值高的问题,提高了间接空冷机组循环水中小于10μg/L痕量铝测定的准确性。

Trace aluminum in SCAL type indirect air cooling unit circulating water was determined by graphite furnace atomic absorption spectrophotometry,the experimental conditions were optimized from the aspects of the working pa-rameters of graphite furnace,matrix modifier,reagent blank,and water sample pretreatment methods.The experimental results showed that the linear correlation coefficient of calibration curve with aluminum ion standard solution concentration in the range of 0-20µg/L could reach 0.9998,the relative standard deviation was less than 10%,and the detection limit was 0.5µg/L,when the graphite furnace ashing temperature and atomization temperature were 700℃and 2700℃,respectively,and there was no matrix modifier.The water samples were acidified for 1 hour and then directly determined.The measured values were compared with the standard heating digestion method.The deviation was within the range of 5.0%,and the blank value was less than 0.5µg/L,which effectively solved the problem of the high blank value of the heating digestion method,and improved the accuracy of the determination of trace aluminum less than 10µg/L in the circulating water of indirect air cooling unit.