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硅酸岩和化探样品中微量溴的催化—分光光度法测定 总被引：1，自引：0，他引：1
硅酸岩和化探样品中溴的含量甚微,一般在10ppm以下,这就要求有一个灵敏度较高的分析方法。一般的比色法和离子选择性电极法灵敏度太低,而灵敏度较高的中子活化法则又缺乏特殊装备不能应用。国外对利用动力学分析法测定溴的研究早有报导,1959年Shiota等用催化法在天然水中测定了微量溴。 相似文献
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地质样品中痕量溴的间接极谱法测定 总被引：1，自引：0，他引：1
提出了一种简便,灵敏的测定地质样品中痕量溴的新方法。半熔法分解样品,利用溴催化高锰酸钾氧化碘化钾的反应,在催化反应进行到一定时间后,用四氯化碳萃取未反应的游离碘,在水相中测定碘酸根的导数极谱波,间接测定溴的含量,本法测定溴的检出限为０．１８μｇ／ｇ,ＲＳＤ为５．７％。标准物质分析结果与推荐值一致。 相似文献
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微波消解-电感耦合等离子体质谱法测定煤中的硼 总被引：3，自引：3，他引：0
煤中硼的准确测定对于研究成煤的沉积环境具有重要意义。微波消解-电感耦合等离子体质谱(ICP-MS)可以有效地测定煤中的大部分微量元素,但由于硼易挥发等特殊的物理化学性质,致使硼的测定过程较为繁琐,测试结果不够准确。本文对微波消解ICP-MS测定煤中硼含量的分析方法进行了改进。样品中加入磷酸、硝酸和氢氟酸,用微波消解仪消解完全,置于电热板加热赶酸完毕后用硝酸提取。硼的卤化物易挥发,磷酸的加入使硼与磷酸结合生成难挥发的稳定络合物,起到了固硼的作用。ICP-MS测定中采用铍作为内标,通过在线加入的方式有效地补偿了基体效应产生的影响;用稀氨水冲洗进样系统,很好地降低了硼的记忆效应;选择高分辨率模式来测定,避免了12C和40Ar4+等质谱峰的干扰。方法的仪器检出限(0.22ng/mL)和方法检出限(0.34 ng/mL)较低,方法精密度(RSD)小于0.6%,灵敏度高,且测定标准样品的准确度良好。该方法简单快速,适用于批量分析煤样中硼的含量。 相似文献
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目前硅灰石的测定,都用间接法,即从酸溶全钙量减去石榴石、白云石、方解石中所含的钙,从而间接计算出硅灰石的含量。这样做容易带来各种误差。硅量法可直接测出硅灰石含量,方法简便快速、成本低。如仅测定硅灰石的含量时,无须测定其他项目。用本法测得的结果和钙量法测定结果是吻合的。一、方法依据根据测出的二氧化硅的含量,即可按硅灰石的组成〔CaO、SiO_2〕直接得出硅灰石 相似文献
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介绍了采用自然集积法湿式测定工业、居住、交通混合区的大气降尘总量,以双氧水和硝酸消解法消解降尘样品,用火焰原子吸收分光光度法测定大气降尘中重金属元素（主要是铅、镉）的含量,并初步研究了降尘及重金属随时间的分布规律：一年中降尘量最大值出现在3月份,最小值出现在6、12月份等。 相似文献
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钨在各类岩石中的平均含量较低,一般为0.1—1ppm。为了满足地球化学研究的需要,测定下限通常需低于1ppm。这样的分析下限只有用活化分析法,或其它化学预富集测定法才能达到。原子发射光谱法直接测定地质样品中钨的主要困难是测定下限不足。常用的垂直电极蒸发法仅达0.01％,水平电极撒(吹)样法稍低,达0.00x％,测定下限最低的是ICP直接粉末进样法,但也仅达Xppm。 相似文献
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地表水污染源的准确识别对于突发水污染事件中制定补救策略、确定责任方具有重要的指导意义。从污染源识别的基本问题出发,综述了地表水污染源识别的两类方法,一类是数学模拟法,包括直接求解法和间接求解法,直接求解法又包括解析法和正则化方法,间接求解法又包括模拟优化法、概率统计法及耦合算法;另一类是足迹分析法。在此基础上,系统地讨论了污染源识别的不确定性,包括污染源信息、观测数据、地表水模型、水动力条件、污染物性质5个方面。并指出地表水污染源识别的不确定性和时效性是制约其应用价值的关键因素,需要在方法耦合、识别效率提高、不确定性分析及污染物性质等方面做进一步的研究。 相似文献
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Environmental legislation has had significant impact on coal utilization, especially coal combustion for power generation, in limiting emissions of potentially hazardous materials to the environment. For the most part, such emissions derive from the inorganic constituents in coal. However, as such legislation becomes ever more encompassing, it has increased the need to understand better the behavior of the inorganic species in coal processing to ensure, in part, that such legislation is not unduly burdensome. Consequently, it has led to significant development of new models for the behavior of inorganics in coal combustion and a complementary enhancement of many analytical methods for determining inorganics in coal.In this paper, analytical methods for inorganics in coal are reviewed on three fronts: (i) methods for determining elemental concentrations; (ii) methods for determining the mineralogy of coals; and (iii) methods for determining modes of occurrence (speciation) of trace elements in coal. The concept of association with respect to mineral–maceral and mineral–mineral occurrences is also discussed. Where possible, comparison of different analysis methods has been made by reference to data on well-characterized suites of coals, such as the Argonne premium coal samples.Incremental enhancements will continue to be made in analytical methods for elemental concentrations; however, major improvements are needed in the other two areas. There is a great need to verify and corroborate by direct speciation methods, the many inferences made by indirect methods regarding trace element speciation. Also, improvements in the measurement of mineral association and its integration into the coal mineral analysis by means of the computer-controlled scanning electron microscopy (CCSEM) would be a significant advance. Accurate determinations of both association and coal mineralogy would lead to significant and much-needed refinements of models for the behavior of inorganics in both coal cleaning processes and coal combustion. 相似文献
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电感耦合等离子体发射光谱法测定铝土矿中镓——酸溶和碱熔预处理方法比较 总被引：4，自引：3，他引：1
研究了盐酸-硝酸-氢氟酸-高氯酸酸溶和氢氧化钠碱熔两种测定铝土矿石样品中镓的前处理方法,利用电感耦合等离子体发射光谱法(ICP-AES)进行测定。对熔矿试剂及条件、分析谱线的选择和元素的干扰进行了讨论,采用不同含量的铝土矿石国家标准物质样品进行了条件实验。分析结果表明:采用盐酸-硝酸-氢氟酸-高氯酸溶解样品,会导致铝土矿石样品溶解不完全,得到的数据失真;而采用氢氧化钠碱熔法处理铝土矿石样品后,用ICP-AES法测定,镓的测定值准确度高,方法检出限为0.15μg/g,相对标准偏差(RSD,n=11)为2.51%～5.97%,回收率为94.8%～108.2%。该方法灵敏度高,精密度好,分析时间短,易于流程操作。方法经国家一级标准物质分析验证,测定结果与标准值相符,特别适用于铝土矿石样品中镓的测定。 相似文献
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Measuring the gas content of coal: A review 总被引：3，自引：0，他引：3
Coalbed gas content measurements are commonly used in mine safety as well as coalbed methane resource assessment and recovery applications. Gas content determination techniques generally fall into two categories: (1) direct methods which actually measure the volume of gas released from a coal sample sealed into a desorption canister and (2) indirect methods based on empirical correlations, or laboratory derived sorption isotherm gas storage capacity data. Direct gas content determination techniques may be further subdivided into quick-crushing and extended desorption methods. The quick-crushing methods are primarily used in mine safety applications outside the United States, but have also been used for resource recovery applications. Quick-crushing methods rely on crushing the coal sample soon after collection to release all the desorbable gas, thus significantly shortening the amount of time required for desorption measurements. However, some data useful for resource recovery applications are lost. Extended desorption techniques are most commonly used for resource assessment and recovery applications where information on desorption rates is useful for reservoir modeling, and for fundamental coalbed methane research. Extended desorption methods allow the gases in the coal sample to desorb under controlled laboratory conditions until a defined low desorption rate cutoff point is reached. The sample may then be crushed to measure the amount of gas remaining within the sample. Direct method techniques for gas content measurement are the focus of this paper. 相似文献
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煤与瓦斯突出预报的模糊聚类相似分析法 总被引：6，自引：1，他引：6
秦书玉 《中国地质灾害与防治学报》2003,14(4):58-61
影响煤与瓦斯突出的因素多数是定性的或是模糊相似，采用模糊聚类分析方法对煤炭与瓦斯突出程度进行分析，建立模糊模式；应用模糊相似选择原理进行评价，以模糊模式为评价对象，以待预报样本为参考对象，根据模糊模式与以待预报样本的相似程度进行预测预报。哪一模式与预报样本最相近，等待预报样本即属于那一突出类型。采用模糊聚类及模糊相似原理2种方法结合分析预测，不仅克服了模糊聚类单一分析方法的不确定性，使定性预报转为定量预报，而且提高了预报效果的准确程度。实例分析表明，这是预报煤与瓦斯突出危险程度的一种较好的方法。 相似文献
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Maria F. Gazulla Maria P. Gómez Mónica Orduña Eulalia Zumaquero Sonia Vicente 《Geostandards and Geoanalytical Research》2009,33(1):71-84
A study has been undertaken to determine sulfur in geological samples by coupled analytical techniques. Two measurement methods have been developed: one using an electric furnace coupled to an ion chromatograph (electric furnace-IC) and another using infrared (IR) and quadrupole mass spectrometry (QMS) for evolved gas analysis (EGA) coupled with a thermogravimetric analyser (TGA). In the electric furnace-IC method, measurement was performed without any sample pre-treatment. The measurement conditions were optimised by varying sample quantity, type of catalyst (WO3 , Cu, W and V2 O5 ) and sample/catalyst ratio, and the detection limit was 10 μg g−1 . Sulfur ores decompose at different temperatures. However, TGA-EGA allowed identification of the different forms of sulfur in the sample, even when they were found in very low concentrations, because the sulfur was continuously analysed. The developed chromatographic method allowed simultaneous analysis of several sample components, such as S, Cl and F, with a low detection limit. The method was much faster and more specific than the methods described in the literature. The results of the sulfur determination had low scatter, possibly because the samples underwent little handling during analysis: the operator only weighed and placed the sample in the furnace, the rest of the measurement process was fully automated. The results obtained by both the developed methods have been validated by using reference materials and comparison with combustion-IR spectroscopy, a standard method for determining total sulfur in a sample. 相似文献
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衍生化气相色谱-质谱法测定复垦土地样品中19种酚类污染物 总被引：2，自引：1，他引：1
近年来国家对自然环境的保护愈加重视,更多被破坏或污染的土地需要进行复垦整治。在评价效果时,需要检测酚类等多项污染物指标。采用气相色谱与气相色谱-质谱联用等方法对酚类化合物直接测定时,存在色谱响应值低、稳定性差、检出限高等问题。本文针对复垦土地样品基质复杂、干扰因素多、前处理困难等特点,对该类样品的提取与净化方法进行筛选优化。根据酚类污染物检测中浓度范围大、重现性差等问题,对衍生化与非衍生化效果进行对比确定了提取和净化方法,结合衍生化条件的优化、实际样品测定结果等方面的综合研究,建立了复垦土地样品19种酚类污染物(其中2,4,6-三氯苯酚和2,4,5-三氯苯酚,以及2,3,4,5-四氯酚和2,3,5,6-四氯酚,因无法分离而合并计算)的衍生化气相色谱-质谱检测方法。该方法采用加速溶剂萃取仪,以正己烷-丙酮(体积比1∶1)提取样品,提取液经浓缩、净化后,由五氟苄基溴衍生化,气相色谱-质谱联用仪测定。该方法基质加标回收率为73.3%~107.0%,检出限为0.67~3.95μg/kg,相比非衍生化方法的检出限(10~80μg/kg)显著降低;并且衍生物的稳定性更好,色谱响应值更高,各组分表现在色谱图上的峰高(峰面积)更均衡,对于低浓度样品的测定结果更加准确。该方法能有效去除基质干扰,可为复杂基质土壤样品中的酚类污染物痕量检测提供参考。 相似文献
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汞分析仪直接测定矿石中的痕量汞 总被引：1，自引：0，他引：1
使用汞分析仪直接对不同矿石中的痕量汞进行快速准确测定。矿样直接称样后,无需复杂的湿法消解或样品前处理,6 min内即可完成汞的测定。建立的方法不受样品性质影响,无基体干扰,方法回收率为90.0%～109.0%,检出限为0.60 ng/g,相对标准偏差(RSD,n=8)为0.95%～4.74%。使用该法分析了6大类矿石标准参考物质和实际样品,并与常规方法进行比较,分析结果与证书值和其他方法测定值一致。与现行国家标准分析方法相比,该方法大大缩短了分析周期,适合大批量试样的分析。 相似文献