浊点萃取-邻二氮菲分光光度法测定海水中痕量铁

来源期刊：冶金分析2010年第10期

论文作者：宋兴良 梁恕坤

文章页码：70 - 73

关键词：浊点萃取； 分光光度法； 聚乙二醇； 邻二氮菲； 铁

Key words：cloud point extraction； spectrophotometry； polyethylene glycol； orthophenanthroline； iron

摘    要：以邻二氮菲(Phen)为显色剂、聚乙二醇6000(PEG6000)为表面活性剂,建立了浊点萃取-分光光度法测定海水中痕量铁的方法。该方法基于表面活性剂的浊点现象,Fe²⁺与邻二氮菲(Phen)生成稳定络合物Fe(Phen)₃²⁺后被定量萃取进入富胶束相中,从而实现与基体的分离,然后萃取相经适当的处理并采用分光光度法进行测定。考察了显色剂浓度、显色温度、萃取时间和PEG6000用量等条件对浊点萃取-分光光度法测定灵敏度的影响。在优化条件下,本法对铁的检出限为4.1×10^-3 μg/mL(富集倍数为18)。该方法应用于海水中痕量铁的分析时,测定值与ICP-AES法的结果相一致,相对标准偏差(RSD)为3.8%~4.5%,加标回收率在86%与95%之间。

Abstract: A determination method of trace iron in seawater by cloud point extraction-spectrophotometry was established using orthophenanthroline (Phen) as coloring reagent and polyethylene glycol 6000(PEG6000) as surfactant.This method was based on the cloud point phenomenon of surfactant.Fe²⁺ could form stable complex Fe(Phen)₃²⁺ with Phen,which was then quantitatively extracted into micellar-rich phase,realizing the separation from matrix.The extraction phase was properly treated and determined by spectrophotometry.The effect of coloring reagent concentration,coloring temperature,extraction time and the dosage of PEG6000 on the determination sensitivity of cloud point extraction-spectrophotometry was investigated.Under the optimal conditions,the detection limit of iron was 4.1×10^-3 μg/mL(the concentration factor of 18).The proposed method had been applied to the determination of trace iron in seawater.The results were consistent with those obtained by ICP-AES,the relative standard deviations (RSD) were 3.8%-4.5%,and the recovery of standard addition were 86%-95%.