ICP-OES测定浮游有孔虫的Mg/Ca比值及其在SST分析中的应用

海洋是驱动大气环流的主要“引擎”，海表温度（SST）又是揭示海洋环境变化的重要参数。利用有孔虫Mg/Ca比值恢复SST具有较高精密度，是目前恢复SST较成功的方法之一。本论文旨在建立一套有效的有孔虫清洗方法和ICP-OES测试有孔虫Mg/Ca比值的分析方法。 文中分析了53份西菲律宾海区(N18°40.23′，E135°37.11′；水深3225m)表层沉积物中浮游有孔虫Globigerinoides ruber（白色）Mg/Ca比值。结合本研究区的特点，文中使用的清洗方法是有孔虫Mg/Ca比值测试常用的“Mg”清洗方法，主要是由以下步骤构成：①用超纯水和甲醇在超声波水浴中清洗，②显微镜下剔除深色硅酸盐颗粒，③用氧化试剂去除有机质(加入30%H2O2和0.1M NaOH溶液在90℃左右的沸水浴中加热)，④酸洗(250μl 0.001N HNO3 超声波水浴中清洗10S)。清洗干净的样品经超纯硝酸溶解成溶液后，利用电感耦合等离子体发射光谱(ICP-OES)对其进行Mg/Ca比值的分析测试。仪器操作条件如下：辅助气流量（Ar）为0.5L/min（0.5L/min-1.5L/min），雾化器压力为0.2Mpa（0-0.4Mpa），泵速为20rpm（0-125rpm），高频输出功率（RF）为1150W（750W-1500W），火焰高度为15.5mm（8-21mm），通过多次重复测量一组Mg/Ca=3.333mmol/mol的标准溶液，其Mg/Ca短期精密度<0.5%,长期精密度为1%。53份样品之间Mg/Ca比值的RSD为2.7%，利用Lea(2000)建立的太平洋地区浮游有孔虫G. ruber(白色)的Mg/Ca与SST的校正公式:Mg/Ca(mmol/mol) ＝0.30exp[0.089×SST(℃)]，得到本研究区的SST为28℃±0.3℃。

利用MC-ICP-MS测定硼同位素及其在西藏地热和盐湖中的初步应用

Based on previous studies, boron can be separated from aqueous samples with Amberlite IRA-743 resin. Experiments on the elute temperature, elute volume and the dynamic resin exchange capacity have been performed in this study. Results show that the dynamic exchange capacity of the resin is 4.2mg B/g and at room temperature, boron fixed on the resin within this capacity level can be extracted quantitatively by using 5ml 2%HNO3. A new procedure has been developed for the measurement of boron isotope ratios in water samples using a Neptune MC-ICP-MS, after resolving the memory effect, which is a key problem, and investigating the impacts of mass bias and Si matrix effect. Using this method, it usually takes 20 min to perform one measurement on 0.1ppm boron solution with a precision of 0.23‰ (SD). If the relative deviation between a sample and the standard is large, the washout time needs to be doubled to achieve a higher precision. δ11B values of water samples from Yangbajing geothermal field vary from -10.53 to -9.13‰. Owing to the large difference B concentration and the small B isotope difference between deep geothermal water and surface water, B isotope ratios of the shallow geothermal fluids are dominated by the deep end member rather than the shallower one in the mixing process. As a consequence, δ11B-B relation is indicative basically of a dilution process. Vapor-liquid separation and calcite scaling also greatly influence B isotope fractionation. δ11B values of water samples from Dagejia geothermal field are from -15.98‰ to -11.67‰. Boron in Changma River near the field has two sources, freshwater lakes (Dajiamang Lake and Canke Lake) and geothermal waters. Finally, a preliminary discussion is included on boron geochemical characteristics of the salt lakes in Shuanghu area and other geothermal fields, to provide information for future studies on boron isotope geochemistry of geothermal systems and salt lakes in Tibet.

Lu-Hf同位素的MC-ICP-MS实验方法及其在华北克拉通典型火山岩研究中的应用

Over past ten years, a great development has been made in the Lu-Hf isotopic system with the advent of MC-ICP-MS. Based on a comprehensive review of available references in the related field, a novel analytical protocol of three exchange chromatographies after one mixed acid attacking geological samples was developed in this work, which not only avoids common multiple sample treatments for natural inhomegeneous samples, but also is useful for Rb-Sr, Sm-Nd and Lu-Hf isotopic system simultaneously, especially for the garnet- and apatite-bearing rocks for the Sm-Nd and Lu-Hf geochronology. An analytical procedure for the Lu and Hf concentration in geological samples determined by by ID-MC-ICP-MS was detailedly investigated. The Hf yield is > 90 % and total procedural blank is less than. 50 pg for Hf and 10 pg for Lu, respectively. The developed method was successfully applied to the determination of Lu and Hf concentrations for USGS geological materials. A one-column procedure for Hf purification in geological samples using common anion exchange chromatography and its isotopic analyses by MC-ICP-MS were also established. Multiple analyses of Standard Reference Materials demonstrate that this method was simple, time-saving, cheap and efficient, especially suitable for the Hf isotopic compositions of young samples. Finally, the measurements of Sr and Nd isotopic compositions using Neptune MC-ICP-MS were described briefly, which indicates that Neptune MC-ICP-MS can precisely measure Sr and Nd isotopic compositions as the TIMS does, even more efficient and less time-consuming than the TIMS method. The Hf isotopic characteristics of typical volcanic rocks (Cenozoic Changle-Linqu basalts, Mesozoic Fangcheng basalts, Mesozoic Jianguo basalts, Mesozoic Wulahada high-Mg andesite, Cenozoic Fanshi, Zuoquan and Xiyang-Pingding basalts of the Taihang Mountains, Paleozoic diamondiferous Menyin and Fuxian Kimblites) from the North China Craton were firstly studied in this work. Coupled with Nd isotopic compositions, it shows that the Hf isotopes could be a better tracer for mantle sources than the Nd isotopes. Individual kimberlite fields from both the Mengyin and Fuxian regions have quite uniform Hf isotopic compositions, similar to the situation for the Nd isotopes.

ICP-MS测定表生水体稀土过程中pH值对酸性膦萃取稀土效率的影响

针对目前最常用的液- 液萃取、ICP- M S 测定法检测表生水体中微量稀土元素方法, 研究了不同pH值条件下, 酸性膦(65%HDEHP 和35%H2M EHP) 自表生水体中萃取稀土元素(REEs) 的回收率。结果表明, 在pH1～ 4 的范围内, 不同性质的水体(湖泊、河流、地下水) 有不同的REEs 回收率。其中湖水在pH 118～ 317 有90% 以上的回收率, 最高回收率为93164%; 河水在pH 211～ 315 范围内有90% 以上的回收率, 最高回收率为95152%; 地下水仅在pH 113～ 115 时回收率超过90% , 最高回收率为97161%。说明在萃取不同表生水体中稀土元素时, 需要调到特定的pH 值才能得到最好的萃取效果。

硒、锌同位素MC-ICP-MS分析方法研究及其在生物和环境样品中的应用

一定元素的同位素组成被认为是该元素特有的“指纹”，同位素组成测量是地球化学、生命科学、环境化学、地质科学和核科学等领域重要的研究手段。利用同位素技术开展生命过程，地球系统中的物理、化学、生物过程及其资源、环境与灾害效应，资源勘探，污染物溯源等方面的研究，既是该技术的前沿研究主题，也使相关领域的研究更加“精细量化”，从而在新的科学纵深揭示出更加清晰的规律。 1992年多接收电感耦合等离子体质谱仪(MC-ICP-MS)的问世，为同位素分析提供了一种强有力的技术手段，与传统的热电离同位素质谱相比，MC-ICP-MS具有测量速度快、操作简便、灵敏度高等优点。而且，由于等离子体源产生的高温，在理论上能测量所有的金属元素和一些非金属元素，并已很好地解决了一些高电离电位元素同位素测量的难题（如Se, Zn, Hf等），用MC-ICP-MS准确、精密测量各种元素同位素组成的方法正在逐渐得到发展和完善。目前，MC-ICP-MS比较成熟的方法主要是针对核和地质科学研究中应用较多的U, Pb, Sm, Nd, Sr, Hf, B, Li等，在硒和锌同位素测量方法学的研究还相对较少（尤其是硒），对一些测量中受各种干扰较为严重的、原子量小于80 的元素同位素的测量技术还有待进一步深入探索和研究。锌、硒元素不仅与人类健康息息相关，而且随着质谱分析技术的发展，使其在环境地球化学、生命科学等领域有着广泛的应用前景。准确测量生物、食品、环境、地质等样品中的锌、硒元素含量、各种形态及其同位素组成受到越来越多的关注。锌、硒同位素准确测量的方法学研究，不仅可以广泛应用于各相关领域，也为锌和硒同位素基、标准物质研制奠定技术基础，从而为锌、硒元素含量和同位素测量提供量值溯源保障。 本工作针对锌和硒元素同位素组成以及生物、环境等样品中成分量准确测量存在的问题，通过使用六极杆碰撞室MC-ICP-MS进行准确测量锌和硒元素同位素的技术研究，结合在化学计量研究中的长期实践及相关文献，从方法学角度和应用方面得出以下结论： 1.MC-ICP-MS仪器测量主要参数，如炬管轴向位置、载气流量、碰撞气流量、仪器稳定性等对测量结果影响很大，要获得高精度的测量结果，须优化和固定参数设置，保持仪器的稳定状态。在六极杆碰撞室MC-ICP-MS测量锌同位素时，高纯氩气碰撞气模式是较为理想的模式，64Zn/66Zn、67Zn/66Zn、68Zn/66Zn同位素丰度比测量精度达到0.002－0.008％，70Zn/66Zn 测量精度达到0.01％；在高纯氢气和氩气碰撞气按一定比例混合的模式下， 76Se/80Se、77Se/80Se、78Se/80Se、82Se/80Se同位素丰度比测量精度达到0.004－0.005%。 2.采用高纯、高浓缩64Zn和66Zn配制了8个校正样品 (64Zn/66Zn：0.6－2.2)；用高纯、高浓缩同位素76Se和82Se配制了16个校正样品（76Se/82Se： 0.05－11.8），用这些样品分别测量并计算了仪器系统误差校正系数K，这些校正样品的K64/66 和 K76/82的相对标准偏差分别为0.034％和0.03％，均在仪器的测量不确定度范围内，说明在校正样品同位素变化范围内，仪器测量同位素丰度比的校正系数没有发生明显变化。 3.在硒同位素丰度比值测量中，氢气碰撞气的使用是SeH产生的重要原因之一，Ar/H在2－7之间都可以满足硒同位素比值测量的要求，即保证较高的硒灵敏度、较小的SeH生成比例、稳定的同位素比值测量结果。本工作建立了SeH的校正计算公式，在对测量结果的质量歧视进行校正时，77Se和78Se的校正更为复杂，因为它们除自身产生的SeH外，还分别受到了来自76SeH和77SeH的影响，故校正质量偏移时应首先对SeH进行校正。对于不同的SeH生成比例，经过校正后，硒的同位素丰度比校正值是一致的，并不受SeH生成比例变化影响。 4.通过对IDMS过程中的关键技术研究，明确了如何正确使用该方法以获得准确测量结果。IDMS方法在测量步骤中引入的不确定度影响因素相对于其它化学分析方法较少，并且可以被明确地表达出来，测量结果可直接溯源到国际单位，因此，该方法对化学计量学研究具有十分重要的意义。 5.建立了适用于ICP-MS测量血清、大豆粉、金枪鱼等多种复杂基体中锌和硒元素的样品前处理方法，建立了锌和硒的ICP-IDMS测量方法。将建立的方法应用于人血清标准物质研制、国家计量院之间的国际比对和合作研究中，取得的优异成绩验证了所建方法的可靠性和可比性。IDMS方法在样品前处理上不怕样品损失和高精度同位素丰度比测量的优点，使其在复杂基体中硒、锌的准确测量方面较其它分析方法具有独特的优势，可在生物、临床、环境、食品等方面的分析研究中广泛应用。

运用MC-ICP-MS测定天然样品的锂同位素组成

自然界锂同位素分馏强烈，这使得它在很多方面都得到了应用，如地球化学、天体化学和核工业等。所有这些领域都要求精确的测定6Li/7Li的比值。但由于锂是微量元素，而且在测试过程中还存在明显的干扰，因此在进行锂同位素比值测定之前必须对样品进行分离和富集。本文以锂元素标准样品和钾、钠、钙、镁元素标准样品的混合溶液为主要研究对象，采用阳离子交换树脂AG-50W-X8来分离富集锂，探索在不同淋洗介质条件下锂分离纯化的最佳介质条件。初步得出以下结论： 1、本次研究建立了相对简单、高效的锂同位素分离方法。用单一的柱子分离、提纯样品锂；用低浓度的盐酸（0.15M HCl）直接作为淋洗介质，操作过程简单。 2、对锂同位素比值测定产生潜在影响因素，如基体效应、回收率、流程空白等进行了实验研究，证实这些影响因素对于本次研究所建立的方法来说都是可以忽略不计的。 3、用MC-ICP-MS测定样品的锂同位素组成，分析结果的准确度和精度与现阶段所报道数据相同。测定海水的锂同位素组成（+31.6±1.0‰，2σ）与Tomoscak 等（+31.8±1.9‰，2σ）的分析值相近。 4、该方法也适用于低含量的样品。我们分离并测定了不同类型样品的锂同位素组成，样品锂含量在0.064µg/g和132µg/g之间，说明该方法也同样适用于低含量地质样品的分析测定。

Interface of chip-based capillary electrophoresis-inductively coupled plasma-atomic emission spectrometry (CE-ICP-AES)

An interface of chip-based capillary electrophoresis (CE)-inductively coupled plasma-atomic emission spectrometry (ICP-AES) that is based on cross-flow nebulization has been developed. A polydimethylsiloxane (PDMS) CE-chip with conventional cross channel layout was used. A stainless steel tube was placed orthogonal to the exit of the CE separation channel for cross flow nebulization. A supplementary flow of buffer solution at the channel exit was used to improve nebulization efficiency. Two capillaries were inserted into the CE chip near the inlet of the separation channel for sample and buffer solution injection. Syringe pumps were used to manipulate the flow rate and flow direction of the sample, buffer, and supplementary buffer solution. Peak broadening due to the shape (bulb and tube-shaped) and size of the spray chambers was studied. The smaller tube-shaped spray chamber was used because of smaller peak broadening effect due to aerosol transport. The nebulization and transport efficiency of the CE-ICP interface was approximately 10%. Ba2+ and Mg2+ ions were eluted from the CE-chip within 30 s. Resolution of the Ba2+ and Mg2+ peaks was 0.7 using the chip-based CE-ICP-AES system.

Improving ICP with Easy Implementation for Free Form Surface Matching

Liu, Yonghuai. Improving ICP with Easy Implementation for Free Form Surface Matching. Pattern Recognition, vol. 37, no. 2, pp. 211-226, 2004.

Investigation into mercury bound to biothiols:structural identification using ESI-ion-trap MS and introduction of a method for their HPLC separation with simultaneous detection by ICP-MS and ESI-MS

Mercury in plants or animal tissue is supposed to occur in the form of complexes formed with biologically relevant thiols (biothiols), rather than as free cation. We describe a technique for the separation and molecular identification of mercury and methylmercury complexes derived from their reactions with cysteine (Cys) and glutathione (GS): Hg(Cys)(2), Hg(GS)(2), MeHgCys, MeHgGS. Complexes were characterised by electrospray mass spectrometry (MS) equipped with an ion trap and the fragmentation pattern of MeHgCys was explained by using MP2 and B3LYP calculations, showing the importance of mercury-amine interactions in the gas phase. Chromatographic baseline separation was performed within 10 min with formic acid as the mobile phase on a reversed-phase column. Detection was done by online simultaneous coupling of ES-MS and inductively coupled plasma MS. When the mercury complexes were spiked in real samples (plant extracts), no perturbation of the separation and detection conditions was observed, suggesting that this method is capable of detecting mercury biothiol complexes in plants.

Can we trust mass spectrometry for determination of arsenic peptides in plants:comparison of LC-ICP-MS and LC-ES-MS/ICP-MS with XANES/EXAFS in analysis of Thunbergia alata

The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP-MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L(-1) as arsenate. The approach of formic acid extraction followed by HPLC-ES-MS/ICP-MS identified different As(III)-PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible. Although sulfur sensitivity could be significantly increased when xenon was used as collision gas in ICP-qMS, or when HR-ICP-MS was used in medium resolution, the As:S ratio gave misleading results in the identification of As(III)-PC complexes due to the relatively low resolution of the chromatography system in relation to the variety of As-peptides in plants. Hence only the parallel use of ES-MS/ICP-MS was able to prove the occurrence of such arsenite phytochelatin complexes. Between 55 and 64% of the arsenic was bound to the sulfur of peptides mainly as As(III)(PC(2))(2), As(III)(PC(3)) and As(III)(PC(4)). XANES (X-ray absorption near-edge spectroscopy) measurement, using the freshly exposed plant root directly, confirmed that most of the arsenic is trivalent and binds to S of peptides (53% As-S) while 38% occurred as arsenite and only 9% unchanged as arsenate. EXAFS data confirmed that As-S and As-O bonds occur in the plants. This study confirms, for the first time, that As-peptides can be extracted by formic acid and chromatographically separated on a reversed-phase column without significant decomposition or de-novo synthesis during the extraction step.

Synthesis of nanoporous materials for preconcentration and determination of trace elements by ICP-AES ; Investigation and elimination of the memory effects of mercury, gold, silver and boron in ICP-AES

Nanoporous materials with large surface area and well-ordered pore structure have been synthesized. Thiol groups were grafted on the materials' surface to make heavy metal ion pre-concentration media. The adsorption properties ofthe materials were explored. Mercury, gold and silver can be strongly adsorbed by these materials, even in the presence of alkaline earth metal ion. Though the materials can adsorb other heavy metal ions such as lead and copper, they show differential adsorption ability when several ions are present in solution. The adsorption sequence is: mercury> == silver> copper » lead and cadmium. In the second part of this work, the memory effects of mercury, gold, silver and boron were investigated. The addition of 2% L-cysteine and 1% thiourea eliminates the problems of the three metal ions completely. The wash-out time for mercury dropped from more than 20 minutes to 18 seconds, and the wash-out time for gold decreased from more than 30 minutes to 49 seconds. The memory effect of boron can be reduced by the use of mannitol.