摘要
目前,测定海洋底质中的痕量钴多用中子活化法和原子吸收分光光度法陆,前者仪器昂贵,需中子源,难以普及;后者则需分离干扰元素,手续较烦。分光光度法设备简单,易于推广,但因底质组成复杂,尚未见有这方面的报道。故研究海洋底质中痕量钻的分光光度法对于海洋污染调查具有重要意义。
The complex reaction ofCo^(2+)ion with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol(5-Br-PADAP)in ethyl alcohol-water medium is described and a simple and sensitive spectrophotometric selective procedure for determining trace cobalt in sea-floor sediments and soils has been developed.At pH 2.5—7.0,CO^(2+)ion reacts with 5-Br-PADAP to form a blue-violet complex,the mole ratio of which is Co:R=1:2 as determined by coutinuous variation and mole ratio methods.The complex formed in acid solution has two absorption maxima at 555 and 590nm.The molar absorptivity is 9.0×10^(4)mole^(-1)cm^(-1)at 590nm which was used for all absorbance measurments.Beers law is obeyed for 0—6μg/25ml.The effect of 22 foreign ions on the determination was examined.On the addition of acid(HCl,HNO_(3),H_(2)SO_(4)or H_(3)PO_(4))to the colored solution,the selectivity of the determination can be increased.Micrograms of Fe^(3+),Cu^(2+),Ni^(2+),Hg^(2+)do not interfere with the results.Mllligram amounts of Fe^(3+)can be masked by the addition of Zn-EDTA.The interference of Cr(Ⅵ)and Mo(Ⅵ)can be eliminated by adding hydroxylamine hydrochloride which reduces the Cr(Ⅵ)to Cr(Ⅲ)and forms Colorless complex with Mo(Ⅵ).Cobalt in seafloor sediments has been determined by proposed method with recovery of 94%and 97%and variable coefficient of 3.0%and 4.1%.
作者
徐葆筠
魏永振
刘玉兰
Xu Baoyun;Wei Yongzhen;Liu Yulan(Qingdao Medical College)
出处
《海洋与湖沼》
1983年第2期191-197,共7页
Oceanologia Et Limnologia Sinica
