共查询到19条相似文献,搜索用时 93 毫秒
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铁矿石化学物相分析中硅酸铁的分离测定方法述评 总被引:1,自引:1,他引:0
对铁矿石化学物相分析中硅酸铁的分离测定方法进行了简要述评。介绍了测定硅酸铁矿物相的重要性、硅酸铁的分离和测定方法研究进展等;通过验证实验和测试数据对比,进一步介绍了化学分离测定方法中的亚铁加合计算法的重要意义和实际应用价值。引用文献55篇。 相似文献
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目前食盐和海带产品中碘含量分析主要是总碘含量测定,而无机碘与有机碘形态分析主要依靠大型精密仪器联用技术。本文研制了一种基于硫化碘化银法研制的全固态、无内参液的晶体膜电极(Z-Ⅱ碘探针),采用聚四氟乙烯消化罐微波消解技术,建立了食用盐及海带中的无机碘及有机碘含量测定方法。实验结果表明:食盐中无机碘含量为20mg/kg,有机碘含量为2mg/kg,海带中有机碘含量为2.9×10~3mg/kg。无机碘及有机碘含量分别在10~100mg/kg范围内线性关系良好,加标回收率为97.1%~101.0%,检出限均为1mg/kg。本方法应用于食盐和海带实际样品中的碘含量测定,无机碘和有机碘测定结果的相对标准偏差(RSD)分别小于0.92%和2.49%,且测定结果与国家标准方法和紫外分光光度法的测定结果基本一致。该方法具有试剂耗量少、成本低的特点,操作方便,可应用于有机碘和无机碘含量的测定。 相似文献
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土壤水分测量方法研究综述 总被引:9,自引:0,他引:9
本文简述了土壤水分的形态、分类和表示方法,以及土壤含水量的测定方法。重点对介电法测量土壤水分的方法进行了介绍.提出了我国当前介电法土壤水分传感器参数率定中存在并和值得注意的问题。对几类土壤水分测量方法进行了比较与讨论。 相似文献
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碘量法测定铜矿石中铜方法的改进 总被引:2,自引:1,他引:1
针对铜矿石中铜含量的测定方法——碘量法在应用过程中存在碘的挥发及碘化铜沉淀对碘的吸附所引起的误差问题,通过大量的调研和试验提出改进方案,即在聚乙烯醇存在下碘量法测定铜,增大了碘化铜沉淀的溶解度;聚乙烯醇与碘生成较稳定的络合物,减小了碘的挥发损失,操作简单;聚乙烯醇可直接代替淀粉作指示剂,成本低廉。 相似文献
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碘是活跃元素,价态多,各价态间易相互转化,化学性质不稳定,使用ICP-MS测定土壤、沉积物和岩石样品中的痕量碘,样品前处理和测定结果的稳定性是主要问题。本文采用磷酸-高氯酸高压密闭消解处理样品,提高了样品分解效率,也避免了碘的挥发损失,通过加入0.5mL 20g/L盐酸羟胺溶液将碘还原为I~-,提高了碘的稳定性,再于100℃烘箱中保温至少20min,以稀氨水作介质,降低了ICP-MS测定过程中的记忆效应。方法相对标准偏差(RSD)为4.88%~9.19%,相对误差为-6.90%~8.33%,回收率为92.5%~109.6%,检出限(3s)为0.012μg/g。本方法的测定数据与半熔法一致,解决了当前方法存在的分析流程长、空白高、岩石样品提取不完全、提取装置繁多等问题,可以作为土壤、沉积物、岩石中痕量碘测定方法的一种补充,适合批量样品分析。 相似文献
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HPLC-ICP-MS法研究内蒙古锡盟和新疆塔城高碘地区地下水的总碘及碘形态特征 总被引:1,自引:1,他引:0
长期饮用高碘水将对人体造成危害,地下水总碘及碘形态分析对于高碘地区碘环境地球化学研究具有重要价值。本文采用高效液相色谱-电感耦合等离子体质谱联用技术对内蒙古锡盟与新疆塔城高碘地区地下水总碘及碘形态进行测定。研究表明:锡盟地区地下水中碘以I-形态为主,总碘量维持在200μg/L,个别点位达到600μg/L甚至1700μg/L,呈环状分布,从东北至西南呈现"低-高-低"的分布规律;塔城地区地下水中的碘以IO-3形态为主,总碘量不足100μg/L,个别点位接近200μg/L,呈层状分布,自东向西逐渐升高。分析认为,氧化性的条件利于不同碘形态之间的转化;溶解氧过高或过低都不利于碘的储存;碘会随着可溶性盐的流失而流失;沿河流的流向,下游地势较低,总碘得到积累。本研究结果对于锡盟和塔城地区科学预防甲状腺肿、制定法律法规具有指导作用。 相似文献
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大洋铁锰矿床生长速率测定研究进展 总被引:5,自引:1,他引:5
大洋铁锰矿床的生长速率很慢,通常为数 mm/Ma,其壳层中记录了大洋海水与沉积环境的长期变化历史。常用的生长速率测定方法有:10Be和 U-Th系放射性同位素测年法、生物地层法、磁性地层法、稳定同位素法、基岩年龄推定法,以及经验公式计算法等。对大洋铁锰矿床生长速率的不同测定方法进行了全面回顾和总结,系统介绍了不同方法的原理、适用原则及优缺点,认为10 Be法是最为可靠的生长速率测定方法。在此基础上对大洋铁锰矿床生长速率测定的发展趋向作了预测,认为微区、微量高精度测试技术的运用,以及在深入研究元素与大洋铁锰矿床生长速率关系的基础上,建立合理有效的生长速率经验计算公式,可能是大洋铁锰矿床生长速率测定发展的基本趋势。 相似文献
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Hongxia Yang Wei Liu Bing Li Huijuan Zhang Xiaoduan Liu Dengyun Chen 《Geostandards and Geoanalytical Research》2007,31(4):345-351
Methods based on high performance liquid chromatography coupled with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) for iodine speciation analysis are described. Experiments were performed relating to iodine species, preservative medium and time. The concentration and pH of the buffer are also discussed in relation to separation efficiency. The developed methods allowed the fast and sensitive determination of iodine species with detection limits of 0.025 μg l−1 (as 1) for both iodide and iodate with < 5% relative standard deviation (RSD) for 50 nmol l−1 . Attempts were made to quantify total organo-iodine by size-exclusion chromatography (SEC). By way of example, a number of groundwater samples were analysed by these methods, revealing that iodide is the main iodine species in the sampled waters, but that high concentrations of organo-iodine compounds were observed in some samples as well. In summary, the total concentration and the dominant species of iodine in aquatic freshwater environments is easily and accurately measured using this new method. 相似文献
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Determination of Bromine and Iodine in Twenty-three Geochemical Reference Materials by ICP-MS 总被引:1,自引:0,他引:1
Trace amounts (from nanogram to microgram levels) of bromine and iodine were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in twenty-three geochemical reference materials issued by the GSJ, USGS, IAEA etc. The pyrohydrolysis technique was used to separate bromine and iodine from samples analysed in the form of powder. The accuracy and precision of the experimental values were assessed by the comparative analysis of well established reference materials such as USGS AGV-1, BCR-1 and IGGE GBW07312. The measured values agreed well with reported values within a 10% error range. We also report reliable new data for these elements in these geochemical reference materials. 相似文献
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Michel L. Schlegel Pascal Reiller Nicole Barré Valérie Moulin 《Geochimica et cosmochimica acta》2006,70(22):5536-5551
The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L3-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparables to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d (I-C) of 2.01(4)-2.04(9) Å, which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)-2.07(6) Å), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)-2.16(2) Å). These results are in agreement with previous conclusions from X-ray photoelectron spectroscopy and from electrospray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study. 相似文献
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原子荧光光谱法测定铟中锡 总被引:4,自引:0,他引:4
试验了采用原子荧光光谱法测定铟产品中锡时,以EDTA为络合剂掩蔽铟,利用EDTA与铟和锡形成络合物的稳定常数不同,克服基体铟对锡的正向干扰;优化了仪器测定条件,测定范围w(Sn)为0.001%~1.00%,标准加入回收率为99%~105%。所拟方法用于铟产品中锡的测定,结果与苯基荧光酮比色法和碘量法相符。8次独立分析的精密度(RSD)为2.4%~10%。 相似文献
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电感耦合等离子体质谱法同时测定地下水中硼溴碘 总被引:6,自引:4,他引:2
建立了电感耦合等离子体质谱法同时测定地下水中B、Br、I的方法。选定φ=2%(体积分数)的稀NH3.H2O介质消除碘的记忆效应。采用干扰较少的10B和79Br同位素。B、Br、I在0~10 000 ng/mL呈良好的线性关系。方法的检出限为10B 0.176 ng/mL,79Br 0.876ng/mL,127I 0.132 ng/mL;精密度(RSD,n=12)为10B 2.86%,79Br 3.36%,127I 2.69%;10B的阶梯加标回收率为94.6%~101.5%,79Br为98.3%~104.9%,127I为96.5%~102.0%。 相似文献
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用硝基苯萃取[Cd(Phen)3]^2+I2^-离子对,再用盐酸反萃取,利用氢化物发生-原子荧光光谱法测定镉的含量,从而间接测定碘。实验在pH=5.2的NaAc-HAc缓冲体系下进行,优化了还原剂KBH;中邻菲罗啉的浓度,镉溶液用量,萃取剂硝基苯的用量,反萃取盐酸的酸度,并制备碘的标准曲线,其线性相关系数R2≥0.9942,线性范围0~10ng/mL,精密度为8.5%,检出限0.80ng/mL,利用标准曲线测出水样中碘的浓度为17.78ng/mL,结果令人满意。实验表明,开发原子荧光光谱间接分析方法,使其能够准确测量更多种类的元素,有着十分积极的意义,同时也能够促进该方法得到更广范的应用。 相似文献