共沉淀-离心-X射线荧光法快速测定表层海水中的Fe,Ni,Mn,Cu,Zn,Pb

基于共沉淀的富集作用,采用自制的离心管离心沉淀,以手持式X-射线荧光仪(XRF)测定,由此建立了表层海水中Fe,Ni,Mn,Cu,Zn,Pb的共沉淀-离心-XRF快速分析方法。测定时间为5 min/样;线性范围125μg/L～1 000μg/L,可以满足近岸表层海水中铁和锰的分析要求;基底加标200μg/L回收率为94.5%～116%;连续7次测定6种金属浓度均为500μg/L的海水加标样品,相对标准偏差(RSD)为2.86%～5.85%。与ICP-MS法比较,测定结果无显著性差异。本方法具有化学试剂污染小、方便快捷、可现场快速测定方法等优点。该方法已成功应用于厦门西港和福建九龙江河口表层海水中可溶态铁锰的现场测定,并在现场以手持式XRF对颗粒物中铁锰进行了测定,获得了该海域颗粒物中和海水中铁锰的分布。

Rapid determination of Fe, Ni, Mn, Cu, Zn, Pb in seawater by co-precipitation-centrifuge-X-ray fluorescence spectrometer

Based on the enrichment of co-precipitation with a self-made centrifugal tube and detection with a portable X-ray fluorescence spectrometer(XRF),a rapid method for determination of iron(Fe),nickel(Ni),manganese(Mn),copper(Cu),zinc(Zn) and lead(Pb) in surface seawater was established.The analysis time was 5 min per sample.The linear range was 125 μg/L~1 000 μg/L,and it fulfilled the requirements for the analysis of iron and manganese in coastal surface seawater.The recoveries were between 94.5%~116% with a sample spiked at 200 μg/L;and the relative standard deviations(RSD) were 2.86% ~ 5.85%(n=7) at 500 μg/L.Compared with the ICP-MS method,there was no significant difference between the determination results.The method has the advantages of being less contaminated from the chemical reagents,convenient and fast,and practicable in the field.The method was successfully applied in Xiamen western harbor and Jiulongjiang estuary in Fujian Province to measure dissolvable iron and manganese in surface seawater on boat.With the portable XRF,particulate iron and manganese were determined in field as well.The distributions of iron,manganese in particles and seawater were obtained.