Rapid Analysis of Heavy Metal Ions in Coastal Seawater Using Preconcentration with Precipitation/Co-precipitation on Membrane and Detection with X-Ray Fluorescence
建立了近岸海水中多种重金属(铁、镍、锰、铜、锌及铅)的氢氧化物和硫化物的沉淀/共沉淀-膜富集-X射线荧光测定法。在海水样品中加入沉淀剂,使重金属离子生成氢氧化物或硫化物沉淀。沉淀经过滤截留,富集在膜上,直接以手持式X射线荧光仪检测。富集100 Ml水样时,两种沉淀法的测定线性范围均为12.5~400μg/l,即测定限均为12.5μg/l。对各重金属浓度为100μg/l的试样连续测定7次,相对标准偏差(rSd)为3.7%~6.4%;氢氧化物沉淀法的检出限在1.32~7.84μg/l之间;硫化物沉淀法为1.94~11.0μg/l。用本方法成功测定了厦门近岸海域及九龙江河口海水中的重金属浓度。基于样品酸化与否及过滤先后顺序的不同,本方法可用于海水和河口水样中可溶态、溶解态及游离态重金属的现场快速分析。Membrane pre-concentration methods coupled with hydroxide and sulfide precipitation/co-precipitation and X-ray fluorescence(XRF) detection have been established for the determination of heavy metal ions(Fe,Ni,Mn,Cu,Zn,Pb) in coastal seawaters.The heavy metal ions in seawater samples could form hydroxide/sulfide precipitates by adding the precipitant solution.Then the precipitates containing target metal compounds were filtrated on a membrane and detected with a portable XRF detector.Under the optimized conditions,the linear range was found to be 12.5-400 μg/L metal ions for both precipitation methods,and the determination limit were 12.5 μg/L.The RSDs(n=7) of the two methods were 3.7%-6.4% for a sample containing 100 μg/L of each metal ion.The detection limits were 1.32-7.84 μg/L for hydroxide precipitation method and 1.94-11.0 μg/L for sulfide precipitation method.The proposed method was successfully applied to determine heavy metal ions in seawater samples obtained from Xiamen coastal sea area and Jiulongjiang Estuary.Based on whether the samples are acidified and filtered before or after acidification,the methods established are applicable to fast and on-field analysis of dissolvable,dissolved and free heavy metal ions in coastal and estuary water samples.厦门大学近海海洋环境科学国家重点实验室自主创新研究课题(No.MELRI1001)资助项
