塞曼石墨炉原子吸收法直接测定海水中的铜

DIRECT DETERMINATION OF COPPER IN SEAWATER BY ZEEMAN GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

本文选择酒石酸消除海水基体对铜信号的干扰,用塞曼石墨炉原子吸收法直接测定海水中的铜。从Cu的原子化曲线可知,加入酒石酸后,背景值减小,Cu原子吸收信号增强,且出现时间提前,表明酒石酸是有效的海水基体改进剂。用P.E.Z3030光谱仪测得双蒸水及海水中的元素Cu的特征质量(m。)分别为12.5pg及12.7pg;检测限分别为0.18μg/L和0.19μg/L,表明基体效应已消除,符合海洋监测要求。可用纯Cu标准溶液作校正曲线,以国家海洋局的两个标准海水样品中的Cu评定本法的准确度,相对偏差为0及-4.6%,与经典的经富集后的FAAS法的结果相比,相对偏差在3.0—6.5％范围内。用不同类型的光谱仪测定了30个海水样品,回收率在89—104％范围内。本法操作简便、快速。

Several organic matrix modifiers were examined for eliminating the suppression effect of seawater matrix on Cu signal. Tartaric acid was found to be very effective in eliminating the matrix effect The Cu ato-mization curve indicates that the backeround signal is attenuated and Cu signal is enhanced in the presence of tartaric acid. With a P. E Z3030 spectrometer, the characteristic mass, m. for Cu in seawater and doubled distilled water are 12.7 pg and 12.5 pg respectively and the detection limit (3a) are 0.19ugLr-1 and 0.18ugL-1 respectively. The accuracy of the determination was assessed by: a) comparing our results wiih those obtained by classical FAAS(after enrichment), b) by analysing two National Seawater Standards. The results are satisfactory. 30 seawater samples have been analysed by different models of Zeeman AA spectrometers. The recoveries range between 89-104%. The method is simple and rapid.