Study of Membrane Pre-concentration Coupled with Fast Detection and on-site Application to the Analysis of Trace Heavy Metals in Coastal Seawater

众多重金属元素中，有些是海洋浮游植物生长所必需的微量营养元素，有些则是非生命所需，即使浓度很低也对生命体具有毒害作用。大洋海水中重金属浓度极低，通常在ng•L-1水平。河口及近岸海域由于人为输入的影响，重金属含量较高。了解近岸海域海水中重金属的含量、分布及其形态等，有助于更好地了解重金属的污染来源、环境行为及可能产生的生态毒理效应。目前海水中重金属的分析，一般是将样品采集后带回实验室，进行预处理后再以原子光谱或质谱法测定。由于样品在运输、保存过程中可能引入污染，且重金属形态易发生变化等原因，将导致测定值有较大偏差。因此，现场测定成为海水中重金属分析的发展趋势。 本论文针对现有方法...Some heavy metals are essential trace elements for phytoplankton in marine environment, while some are not and can cause toxic effects even at low concentrations. In open-ocean waters, concentrations of heavy metal are down to ng•L-1 levels. In estuary and coastal area, the concentrations can be higher because of human activities. Study on the concentrations, distributions and species of hea...学位：理学硕士院系专业：海洋与环境学院环境科学与工程系_环境科学学号：2262008115153

Rapid determination of soluble reactive silicate in seawater by flow injection analysis with spectrophotometric detection and its application

基于酸性条件下硅酸盐与钼酸铵反应生成硅钼黄而后被还原成硅钼蓝的原理,利用流动注射分析技术,建立了快速测定海水中活性硅酸盐的分析方法.在优化的条件下,方法检测限为0.5μMOl·l-1,线性范围为2.5~110.0μMOl·l-1,实际海水的加标回收率为103.6%~109.3%,同一水样连续测3次仅需4.5MIn.测定硅浓度11.7μMOl·l-1的南海海水样,相对标准偏差(rSd)为1.6%(n=12).该方法具有简单、快速、水样消耗少、盐度高于14即不干扰测定等优点,成功地用于厦门西港海水中活性硅酸盐浓度的测定.A new flow injection analysis method for rapid determination of soluble reactive silicate in seawater is established based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex,and further reduction to silicomolybdenum blue by ascorbic acid.Under the optimum conditions,the detection limit was 0.5 μmol · L-1;the linear and recovery ranges for real seawater samples were 2.5--110.0 μmol · L-1 and 103.6%--109.3%,respectively.Only 4.5 min was needed to analyze one sample in triplicate.The relative standard deviation(RSD) was 1.6%(n=12) for seawater samples obtained from the South China Sea with a silicate concentration of 11.7 mol · L-1.The proposed method is simple,fast,requires little sample,and showed no interference from salinity(>14).The method was successfully applied to measure the soluble reactive silicate in seawater samples in Xiamen's Western Harbor.国家高技术研究发展计划资助项目(No.2007AA061501)---

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

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。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.近海海洋环境科学国家重点实验室自主创新研究课题(MELRI1001

Determination of Trace Silicate in Water for Semiconductor Industry by Flow Injection Automatic Analysis

硅酸盐在酸性介质中与钼酸铵反应生成硅钼黄,硅钼黄还原为硅钼蓝后,可被Hlb小柱定量萃取。在此基础上,建立了流动注射-固相萃取-分光光度(fI-SPE-VIS)测定水中痕量硅酸盐的新方法。反应生成的硅钼蓝经Hlb小柱萃取后,用水清洗去除杂质,nAOH溶液洗脱,分光光度法检测。实验对各参数进行了优化,优化后的参数为:洗脱剂浓度0.01MOl/l;试样上柱流速28.0Ml/MIn;洗脱流速3.5Ml/MIn;反应温度45℃;硅钼黄与硅钼蓝反应时间均为5MIn;钼酸铵混合溶液、草酸溶液、抗坏血酸溶液的用量分别为3.5,3.5和1.75Ml。本方法具有良好的重现性和灵敏度,测定含硅9.33μg/l的硅酸盐水样7次,rSd值为1.8%;选取不同的试样富集时间,可将定量分析的线性范围扩展为0.47~117μg/l;检出限0.18μg/l;回收率为96.8%~105%。可满足特殊工业用水中痕量硅检测的需要。The silicomolybdenum can be extracted by solid phase extraction technique on HLB column.Combining with sequential-injection analysis technique,a novel method for the determination of trace silicate in freshwater has been established.The silicomolybdenum blue was enriched by HLB column,and pure water was used to clean the column,then the silicomolybdenum blue was eluted by NaOH solution and detected by spectrophotometer.The optimized experimental parameters were as follows:the concentration of the eluent was 0.01 mol/L;the extracting and eluting flow rate was 28.0 and 3.5 mL/min,respectively;the reaction temperature was 45 ℃;the reaction time for both molybdosilicic heteropoly acid and silicomolybdenum blue was 5 min;the volumes of the ammonium molybdate,oxalic acid and ascorbic acid solution were 3.5,3.5 and1.75 mL,respectively.The proposed method showed the advantages of high sensitivity and reproducibility,for a water sample containing 9.33 μg/L Si,the RSD was found to be 1.8%(n=7).The linear range,with different calibration curves,was 0.47-117 μg/L.The detection limit was 0.18 μg/L,and the recovery was in the range of 96.8%-105%.厦门大学2007年度“凌峰计划”资助项

A Device and Rapid Method Without Pretreatment for Determination of Hydrogen Sulfide in Aqueous Samples

建立了免预处理测定水样中硫化氢浓度的快速简便方法.该法利用硫化氢的可气化、可透过气液分离膜的特征使之与复杂基底分离,基于亚甲基蓝比色法原理进行测定.自制PVC采样装置,内装显色剂(对氨基二甲基苯胺与硫酸高铁铵的混合液),以聚四氟乙烯气液分离膜封口;将该装置投入水样中,水中的硫化氢透过分离膜扩散进入装置并与显色剂反应;20 min后用分光光度计测定吸光值.利用标准曲线即可计算水中硫化氢的浓度,亦可通过目视比色法半定量快速检出,测定范围为0.05～10 mg(S2-)/L.本法简单、方便、低成本,省却了繁琐的预处理操作步骤,基底干扰小,可直接测定浑浊水样.本法有望发展成现场及原位的测定方法,用于低浓度硫化氢的定性和半定量快速分析.A rapid and simple method without pretreatment for the determination of hydrogen sulfide in water sample has been developed.It was based on the principle of methylene blue spectrophotometric method.The absorbing/color developing reagent was filled in a self-made PVC device sealed with PTFE membrane.Hydrogen sulfide permeated through PTFE membrane and reacted with the reagent for 20 min.Then the hydrogen sulfide concentration the range of 0.05~10 mg(S2-)/L could be quantified with a calibration curve by a spectrophotometer.The semi-quantitation could also be observed by naked eyes.The proposed method was simple,convenient,and low cost.Without tiresome pretreatment,it was time and labor saving.The complicate matrix would not interfere with the detection,and the direct detection of hydrogen sulfide in water on field or in-situ could be possible.厦门大学“挑战杯”和“凌峰计划”项目资

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