硼硅酸盐矿物硼的化学分离纯化与同位素测定方法

采用碱熔法分解电气石样品,研究了3种不同纯化分离方法对硼回收和同位素测定的影响。实验表明:电气石中富含的Fe³⁺和Al³⁺对甲亚胺-H酸分光光度法测定硼含量有较大干扰,并在硼特效树脂交换分离中形成氢氧化物沉淀,阻塞交换柱;同时吸附溶液中硼元素造成回收率降低。本实验依次采用阴/阳离子混合树脂,硼特效树脂和阴/阳离子混合树脂三步离子交换进行电气石样品的纯化分离方法,实现了复杂基体中硼的完全回收（回收率99%）。在TIMS（Triton TI）采用H3和H4法拉第杯,并通过优化Zoom Optics参数（Focus Quad:15;Dispersion Quad:-85）实现静态双接收硼同位素组成测定。本方法对NIST SRM 951标准样品测定结果为¹¹B/¹⁰B=4.05044±0.00012（2σ,n=8,1μg B）,测定内外精度优于传统的动态峰跳扫。NIST SRM951测定结果为-0.3‰,表明预处理过程中无硼同位素分馏效应。天然样品硼同位素组成分别采用静态多接收PTIMS-Cs₂BO₂⁺法和MC-ICP-MS测定,数据点基本分布在1:1线上,说明MC-ICP-MS测定结果与PTIMS方法结果相一致。     

电感耦合等离子体质谱法测定硼同位素丰度

以硼同位素标准物质NIST SRM 951配制标准溶液,在优化的仪器操作条件下对电感耦合等离子体质谱(ICP-MS)测定的硼同位素质量进行校正,求出校正因子,确定了样品的线性浓度范围,选定样品浓度为1.1 mg/L。在同样的仪器条件下首先测定了硼标准物质的硼同位素丰度比,测量误差为0.2%,然后测定了硼同位素浓缩过程中硼样品的硼同位素丰度比,测定结果的相对标准偏差为1.1%。此外考察了仪器的稳定性。实验结果表明本方法“记忆效应”小,结果可靠,测量精度高。     

珊瑚中硼的分离及其同位素组成的测定

介绍了用硼特效树脂和阴、阳混合离子交换树脂相结合进行珊瑚中硼的分离和纯化方法，满足了正热电离质谱法测定硼同位素的要求，并且对几个珊瑚样品进行了硼的分离和硼同位素组成的测定，结果满意，为研究珊瑚中的硼同位素示踪古海洋环境变化提供了可能。     

正热电离静态多接收偏硼酸铯离子测定硼同位素

利用表面热电离质谱仪(Triton TI)的"Zoom Quad"功能,采用静态多接收偏硼酸钯离子(Cs2BO+2)测定标准样品NIST 951 H3BO3和珊瑚与有孔虫样品的硼同位素,研究了涂样量对硼同位素组成测定的影响,探讨静态多接收与传统的动态峰跳扫方法相比,在测定精度、准确度、样品量以及测试时间上的优势.实验结果表明,在测试精度和准确度相同的情况下,静态双接收所需样品量可以低至0.1 μg,且测试时间可缩短一半.对0.1 μg NIST 951 H3BO3静态双接收测定的硼同位素比值11B/10B = 4.05159±0.00023(2σm, n=10),与世界主要实验室的测试值相符.最后对0.1 μg珊瑚和有孔虫样品进行了测定,也取得了较好的结果.     

三步离子交换方法用于粘土沉积物酸溶相中硼同位素测定

在采用酸溶法进行粘土沉积物中硼同位素组成测定时,大量存在的Al、Fe、稀土等元素在较高pH溶液中会形成能强烈吸附硼的氢氧化物沉淀,对硼的提取和硼同位素的测定产生较大影响.有效去除这些干扰元素一直是测定粘土沉积物酸溶相中硼同位素组成的瓶颈.本实验采用三步离子交换法萃取和纯化粘土沉积物中的硼,以AG 50W×8阳离子树脂柱去除所有能生成水不溶性氢氧化物的Al、Fe、稀土等元素,再采用Amberlite IRA 743硼特效树脂柱提取硼,最后采用Ion-exchangerⅡ与AG 50W×8组成的阴阳离子混合树脂柱进一步纯化硼提取液.结果表明,采用以上三步离子交换法提取粘土沉积物中硼的回收率高于90％,未观察到明显的硼同位素分馏,可满足粘土沉积物酸溶相中硼同位素组成高精度测定的需要.     

植物中硼分离方法的建立及其同位素质谱测定

硼是植物生长所必须的一种微量营养元素,在植物体生殖器官的建成和发育过程中起着关键作用。本实验将干灰化法与两步离子交换色谱法结合,建立了植物中硼的分离富集方法。本方法能够消除大量有机质,硼的回收率达到约100%,能满足硼同位素正热电离质谱法测试的需求。测定结果表明,两种植物中硼的同位素组成变化范围为!19.45‰~5.73‰,平均值为!2.80‰,在植物体不同组织之间存在着非常明显的硼同位素分馏。两种植物的茎中相对富集10B,造成11B相对贫乏,而在花和叶中相对富集11B。为进一步利用同位素技术研究植物生长过程硼的行为和全球硼的循环提供了可能。     

多晶硅中硼含量的密闭消解-ICP-AES法测定

采用恒压密闭消解的方法分解多晶硅样品,电感耦合等离子体原子发射光谱测定多晶硅样品中的硼含量.探讨了酸及络合剂的类型与用量对硼含量测定的影响,优化后的实验条件为:消解体系为2 mL HF+2 mL H2O+0.6 mL HNO3, 络合剂为0.30 mL甘露醇溶液(2.5 g/L),稀释剂为0.3 mol/L的硝酸.在最佳实验条件下,硼元素的回收率为91% ～95%,相对标准偏差均小于5.0%.     

硼-10富集硼烷Lewis碱加合物的合成

天然硼中主要含有两种稳定同位素,即硼-10和硼-11,丰度分别为19.78%和80.22%.其中,富集的硼-10同位素在核工业以及放射治疗癌症等方面有重要应用.因此,硼-10富集含硼化合物的合成具有重要的研究意义.硼烷类化合物是合成这类化合物的主要起始原料,但是目前合成硼-10富集硼烷化合物的方法还比较少.以商业可得的硼-10富集硼酸为起始原料,首先采用改进的文献方法合成了硼-10富集的Na¹⁰BH₄,Na¹⁰BH₄与碘单质反应生成乙硼烷(¹⁰B₂H₆)然后,乙硼烷与各种Lewis碱进行配位,得到了一系列硼-10富集的硼烷Lewis碱加合物,包括四氢呋喃硼烷(THF·¹⁰BH₃)、二甲基硫醚硼烷(DMS·¹⁰BH₃)、N,N-二甲基苯胺硼烷(DMA·¹⁰BH₃)、氨硼烷(NH₃·     

(硬)石膏矿物中硼的提取分离及硼同位素测定

(硬)石膏作为海湖水蒸发过程中常见的硫酸盐矿物,能很好反映原始母液的组成及相关水文地质信息。硼属于易溶元素,常赋存于各种蒸发岩矿物中,目前硼同位素在矿床学,地球化学,古环境等地球科学中已得到广泛应用。由于(硬)石膏硼含量较低且难溶于水和盐酸,所以其硼含量及硼同位素组成特征研究较少。本研究通过物相转化与树脂交换法提取纯化(硬)石膏中的硼:首先使用碳酸氢铵与石膏混合,将微溶硫酸钙转化为难溶碳酸钙,随后使用盐酸溶解,一次转化率为85%,两次转化与分解可以保证石膏的完全溶解;之后经过硼特效树脂(Amberlite IRA 743)完成硼富集及阴阳离子混合树脂(Ion ExchangeⅡ和Dowex50W×8)对硼的纯化;最终通过He改进的正热电离质谱法测定硼同位素。测得试剂石膏中的硼含量为(3.501±0.128)μg/g(n=12,RSD=3.6%),平均加标回收率为100.5%;同时加标试剂石膏的δ~(11)B值为17.98‰±0.21‰(n=3,RSD=1.2%),说明整个流程的重复性良好,可以满足(硬)石膏中硼含量及其硼同位素组成的准确测定。     

电感耦合等离子体原子发射光谱法测定硼铁合金中的硼

采用电感耦合等离子体原子发射光谱法测定硼铁合金中硼。样品经碳酸钠-过氧化钠碱熔后,用盐酸和硝酸溶解,选择硼208.959nm为分析谱线,通过添加铁消除基体效应的影响。方法的检出限(3S/N)为0.005mg·L-1。方法用于硼铁标准样品的分析,测定值与认定值一致,测定值的相对标准偏差(n=6)小于2%。     

Effective elimination of organic matter interference in boron isotopic analysis by thermal ionization mass spectrometry of coral/foraminifera: micro-sublimation technology combined with ion exchange

In order to better estimate the effectiveness of micro-sublimation technology on the elimination of organic matter interference during boron isotopic analysis, a series of improved experiments was carried out using simple apparatus. Recovery rates after micro-sublimation were measured for boric acid solutions with different B contents or different B/organic matter ratios. The improved micro-sublimation procedure combined with ion-exchange technology was then used to test natural samples (coral and foraminifera) for the separation of boron. Our results show that the time taken for 100% recovery of different amounts of B differed and that the proportions of B/organic matter within the natural organic matter have little effect on the relationship between the recovery rates of B and the micro-sublimation times. The experiments further confirm that the organic matter does indeed have an effect on boron isotope analyses by positive thermal ionization mass spectrometry and that the use of micro-sublimation can effectively remove interferences from the organic matter during boron isotopic analysis.     

Determination of boron in organic compounds by microwave plasma–atomic emission spectrometry

We propose a method for the determination of boron in aliphatic and aromatic trifluoroborates (including perfluorinated ones), ethers, and organoboron compounds containing dioxoborolane fragments, pyridine, and pyrazole rings, and triple bonds. The substances were decomposed by the oxygen flask combustion method. Boron was determined on an Agilent 4100 microwave plasma–atomic emission spectrometer. A number of organic compounds were analyzed, and the mass fraction of boron was determined with an error less than ±0.3 abs. %.     

负热电离质谱测定硼同位素的涂样试剂比较

目前人们并未注意到利用负热电离质谱方法测定硼同位素所采用涂样试剂中BO^-的同质异位素CNO^-离子的存在和影响。对硼同位素测定采用的不同涂样试剂进行比较，结果发现在去硼海水和硝酸盐溶液中存在BO2^-的同质异位素CNO^-离子，干扰离子不仅来自有机物，而且可能来自硝酸根。在硼同位素测定中，检查空白中的43峰和43／42比值是必要的。实验表明MgCl2 NaOH混合溶液是负热电离质谱测定硼同位素的较为理想的涂样试剂。     

Volatilization of methyl borate in iron matrix. Determination of boron in steel by ICP atomic emission spectrometry

A rapid and reliable method for the determination of boron by ICP-AES in steels is described. The procedure is based on a discontinuous generation of methyl borate, in concentrated sulphuric acid and phosphoric acid medium, after injecting 45 microl of methanol in 20 microl of sample. The gaseous methyl borate and excess methanol are fed into the ICP torch via the intermediate tube by a flow of 430 ml/min Ar carrier gas, without disturbing the discharge. This work simplifies drastically the existing methodology of boron analysis in steels. Acid-soluble boron has been determined, but acid-insoluble boron can also be determined. The determination is carried out without iron interferences, with a reproducibility of 1.90% r.s.d. for a concentration of 20 microg/ml, and an absolute detection limit of 20 ng of total boron, working with a solution volume of 20 microl.     

有孔虫中硼的分离及其正热电离质谱法测定

针对大洋钻探计划(0DP)钻孔中有孔虫数量少、硼含量低的特点，改进了硼特效树脂和阴、阳混合离子交换树脂相结合进行分离硼的方法，成功地实现了硼的分离，并且首次采用正热电离质语法测定了有孔虫中硼同位素的比值。由于硼的分离过程不产生同位素分馏，测定结果令人满意。     

9,10-二氢化菲在三氟化硼乙醚-浓硫酸混酸中的电化学聚合

在三氟化硼乙醚(BFEE)-浓硫酸混合电解质体系中直接氧化9,10-二氢化菲获得了高质量聚(9,10-二氢化菲)膜, 其电导率为3.8×10－1 S/cm. 9,10-二氢化菲在BFEE＋10%浓硫酸体系中的起始氧化电位为0.93 V vs. SCE, 远低于其在乙腈＋0.1 mol/L Bu4NBF4溶液中的起始氧化电位(1.75 V vs. SCE). 在BFEE＋10%浓硫酸体系中获得的聚(9,10-二氢化菲)膜具有良好的电化学性质. 聚合物部分溶于二甲基亚砜、四氢呋喃、氯仿等极性溶剂. FT-IR和量化计算表明聚合反应主要发生在2, 7位或者3, 6位. 荧光光谱和热重分析表明聚合物是一种良好的蓝色荧光材料且具有良好的热稳定性.     

Aromaticity of planar boron clusters confirmed

Low-energy boron clusters are characterized by two-dimensional geometry. Aromaticity of these planar boron clusters was established in terms of topological resonance energy (TRE). All planar boron clusters were found to be highly aromatic with large positive TREs even if they have 4n pi-electrons. Aromaticity must therefore be the origin of unusual planar or quasi-planar geometry. Thus, the aromaticity concept is as useful in boron chemistry as it is in general organic chemistry. It is evident that the Hückel 4n + 2 rule of aromaticity should not be applied to such polycyclic pi-systems. Some of the boron clusters are in the triplet electronic state to attain higher aromaticity. Multivalency and electron deficiency of boron atoms are responsible for lowering the energies of low-lying pi molecular orbitals and then for enhancing aromaticity. For polycyclic pi-systems, paratropicity does not always indicate antiaromaticity.     

A Soluble Dynamic Complex Strategy for the Solution‐Processed Fabrication of Organic Thin‐Film Transistors of a Boron‐Containing Polycyclic Aromatic Hydrocarbon

The solution‐processed fabrication of thin films of organic semiconductors enables the production of cost‐effective, large‐area organic electronic devices under mild conditions. The formation/dissociation of a dynamic B?N coordination bond can be used for the solution‐processed fabrication of semiconducting films of polycyclic aromatic hydrocarbon (PAH) materials. The poor solubility of a boron‐containing PAH in chloroform, toluene, and chlorobenzene was significantly improved by addition of minor amounts (1 wt % of solvent) of pyridine derivatives, as their coordination to the boron atom suppresses the inherent propensity of the PAHs to form π‐stacks. Spin‐coating solutions of the thus formed Lewis acid–base complexes resulted in the formation of amorphous thin films, which could be converted into polycrystalline films of the boron‐containing PAH upon thermal annealing. Organic thin‐film transistors prepared by this solution process displayed typical p‐type characteristics.     

Synthesis and characterization of processable polyborate precursors

Polyborates have been formed by disproportionation and polycondensation of trimethoxyboroxine and also of trimethoxyboroxine and boric acid. The crtiical role of stoichiometry in the formation of polyborates without requiring incorporation of a metal counter ion is revealed. The emphasis is on integration of this chemistry with fabrication processes. Incorporation of an appropriate linear organic polymer is shown to yield the required rheological and thermal characteristics in this regard. These polyborates are inferred to be suitable as precursors for boron nitride in geometrical forms that can be processed as supported structures. However, they are also determined to be unsuitable as precursors for boron nitride fibers, oriented or isotropic, primarily due to their low glass transition temperature.