【作者】 张伟娜；

【导师】 谢学锦； 郝立波；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2012， 博士

【摘要】 碘是人体合成甲状腺激素必不可少的微量元素，在人体的新陈代谢、生长发育过程中发挥着举足轻重的作用。环境水体是地球化学循环中进行元素转化和迁移的媒介，是人体摄取碘的重要来源。因此研究环境水体中碘元素的存在形态可为进一步研究碘在自然环境中的迁移转化条件和规律提供理论依据，而且还能够准确地评价碘对环境和生态体系的影响。研究碘的分析方法有很多种，其中，电感耦合等离子体质谱技术由于具有较低的检出限、较少的干扰、较高的灵敏度和精密度、较宽的线性范围，而成为环境地球化学中同时检测多个元素的首选技术。将它与其它分离技术联用已成为碘元素形态分析的最有效研究方法。本文以环境水体中碘的存在形态为研究目标，建立了电感耦合等离子体质谱测定碘总量的分析方法和电感耦合等离子体质谱与离子色谱联用测定碘形态的新方法，以此为基础，研究了海水、湖水、地下水和大气降水等环境水体中碘的总量和存在形态，并分析探讨了水体中碘存在形态的影响因素，进而分析不同水体中碘形态转化的原因及其环境地球化学行为。主要研究成果如下：（1）在系统总结环境水体中碘的来源、分布、地球化学循环、碘与人体健康关系的基础上，详细综述了碘总量和形态分析方法的研究进展。（2）研究建立了电感耦合等离子体质谱技术测定碘总量的分析方法。以Lu作内标，仪器经混合标准调谐液优化后建立的测定碘总量的标准曲线线性范围宽达5个数量级，碘的检出限低至0.0218μg/L，精确度高（RSD=3.85%），准确性好（国家标准碘盐的测定结果与标准值相符）。（3）研究建立了一种新的短柱分离离子色谱-电感耦合等离子体质谱联用技术测定碘形态的分析方法。经优化得出最佳的分离条件：Dionex IonPacAG11（4×50mm）作分离柱，8mmol/L的（NH₄）₂CO₃溶液作流动相，流速1.5mL/min、进样量20μL。在该分离条件下以电感耦合等离子体质谱作检测器得到的IO₃^-和I-的线性范围宽（0.1-100μg/L），线性关系良好（相关系数r²均大于0.9996），IO₃^-和I-的检出限低（分别为0.015μg/L和0.081μg/L），精确度高（RSD<4.3%），IO₃^-和I-的分离时间短（170s左右）。（4）采用建立的短柱分离离子色谱-电感耦合等离子体质谱联用技术对市面零售的加碘食盐中碘的形态进行了研究，并分析了经人体循环代谢后尿液中碘的形态。结果表明：市售食盐中的碘均以IO₃^-形态存在，经过人体循环代谢，最终以I-形态随尿排出。为进一步研究IO₃^-在生物体（人体）中的代谢机理提供了基础。从尿碘总量来看长春市民没有碘缺乏病的危险。（5）采用建立的新方法对不同环境水样中碘的含量、形态、形态赋存的原因及其环境地球化学行为进行了研究。结果表明：不同水体中碘的总量和存在形态不尽相同。总体来说海水中碘的含量比陆地水中碘的含量要高。海水和长春南湖水中碘主要以IO₃^-和I-两种形态存在，且含量适中。从长春大气降水判断长春属缺碘区，其中IO₃^-和I-的含量之和还不足碘总量的一半。从长春自来水和地下水中碘含量判断长春属于适碘区，但自来水中碘主要以IO₃^-形态存在而地下水中主要以I-存在，且所占比例都接近100%。（6）研究pH、氧化还原环境、盐度和有机质含量等主要影响因素对碘形态转化的影响。结果表明：IO₃^-形态与氧化剂含量、盐度和有机质含量呈显著相关，与0-50℃的环境水温和4-10的环境水pH值没有明显的相关性。而I-与所有考察的因素均具有较好的相关性，尤其与氧化剂的含量、盐度和有机质含量相关性显著。根据理论Eh-pH图分析的环境水体中碘的存在形态与实际水体中的存在形态有差别，说明环境水体中碘形态受地理位置、环境条件影响较大。更多还原

【Abstract】 Iodine is an essential microelement which can composes hormone of thyroidgland, and it is very important for metabolism and human body’s growth development.Environmental water system is a medium of elementary transformation andtransference in circle of geochemistry, and it is an important source of iodine forhuman body. Therefor, the study on speciation of iodine in environmental watersystem can offer theoretic basis for transferred conditions and rules of iodine inentironment. And it can truly evaluate the influence of iodine on surroundings andecosystem. There are many analytical methods for study of iodine. Inductivelycoupled plasma mass spectrometry （ICP-MS） has been a preferred technique foranalysis of various trace elements in environmental geochemistry owing to its lowlimits of detection, few interferences, high sensitivity and precision, widely dynamiclinearity. The combination of other separation technique with its specific detectiontechniques has become most effective methods for iodine speciation of some specialsamples.The speciation of iodine in environmental water system was selected as target inthis dissertation. Two new methods had been established, one was inductively coupledplasma mass spectrometry technique for determination of total iodine, the other wasion chromatography coupled with inductively coupled plasma mass spectrometrytechnique for speciation analysis of iodine. On the basis of these methods, thecontents of total iodine and its speciation in environmental water system includingseawater, lake water, groundwater and atmosphere precipitation etc had been studied.Finally, the influencing factors which could affect the speciation of iodine, the reasonsof speciation tansform and behaviors in environmental geochemistry of iodine hadbeen discussed.The major results are described as follows:（1） On the basis of summarization on the source, distributing, circle of geochemistry of iodine and the relation of iodine to the human health, progress in thestudy of analytical methods for total iodine and its speciation had been summarized inditail.（2） An analytical method was established for total iodine by ICP-MS with Lu asinternal standard. The stadard curve of total iodine, established on the optimalinstrumental operating parameters which were adjusted by mixed criterion solution,had wide linear ranges which reached to five magnitude, the detection limit of iodinewas0.0218μg/L, the precision was high wih RSD=3.85%, the method was alsovalidated using certified reference materials, and the results were in good agreementwith the certified values, which showed the veracity of method was good.（3） A fast analytical method was developed for speciation of iodine by shortcolumn ion chromatography （IC） coupled with inductively plasma mass spectrometry（ICP-MS）. The optimal separation conditions were obtained after optimization whichwere separation column, Dionex Ion PacAG11（4×50mm）; mobile phase,8mmol/L（NH4）2CO3solution; flow rate,1.5mL/min; injection volume,20μL. Under theoptimal separation conditions and ICP-MS detector, IO₃^-and I-both had wide linearranges （0.1-100μg/L）, good linearity （r2>0.9996）, low detection limits （0.015μg/Land0.081μg/L for IO₃^-and I-, respectively）, high precision （RSD<4.3%）, shortseparation time （nearly170s）.（4） The established short column IC coupled with ICP-MS for Speciation ofiodide and iodate was applied to determination of iodized salts collected from localmarkets and human urine samples collected from volunteers. The results showed thatiodine in the iodized salts firstly existed as IO₃^-and was all transformed to I-after themetabolizing cycle in the human body, which would supply basis to further study onmetabolizing mechanism of IO₃^-in organism （human）. The dangers of IDD inChangchun City was inexistent from the contents of urine iodine.（5） The contents, speciation, reasons of speciation and their behaviors inenvironmental geochemistry of iodine in different environmental water system hadbeen studied by the proposed method in this work. As the results revealed, thecontents and speciation of iodine in different environmental water system weredifferent from each other. In a word, the content of iodine in seawater was higher thanthat in land water. The iodine were existed as IO₃^-and I-in seawater and ChangchunSouth lake water, and the contents were moderate. Changchun was section of iodine deficiency which judged by atmospheric precipitation, the total content of IO₃^-and I-was fewer than half of total iodine. Changchun was section of moderate iodine whichjudged by tap water and groundwater, however, the existent speciations of iodine inthese two waters were IO₃^-for tap water and I-for groundwater, respectively, nealyboth were100%.（6） The infulence of pH value, oxidation-reduction surroundings, salinity andcontent of organic substance on the speciation tansform of iodine had been studied.The results showed that speciation of IO₃^-had remarkable relativity with the contentsof oxidant, salinity and organic substance, by contraries, it had no relativity withwater temperature between0-50oC and pH value between4-10. However, thespeciation of I-had good relativity with all factors, especially with content of oxidant,salinity and content of organic substance. The theoretic species of iodine according tothe diagram of Eh-pH were different to the real species of iodine in environmentalwater system, which revealed that the speciation of iodine in environmental watersystem had been significantly affected by geographical position and environmentalconditions.更多还原