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401.
电感耦合等离子体质谱法测定生物样品中超痕量稀土时氧化物干扰的研究 总被引:11,自引:10,他引:11
试验了100~700ug/LBa的氧化物对Eu产生的干扰,干扰程度与Ba量呈线性,其相关系数r在0.9986~0.9995。用模拟样品溶液对不同含量的Ba对Eu的干扰采取了简单的数学方法校正,校正后的结果在误差允许范围之内。.对小麦和人发标准物质中Ba氧化物对Eu的干扰及校正效果进行了比较。结果表明,在所使用的仪器条件下,这两个标准物质中的Ba对Eu的干扰必须校正。研究了ug/L水平的轻稀土氧化物对重稀 相似文献
402.
华北克拉通北缘元古宙大庙Fe-Ti-P矿床的挥发份组成和C-H-O同位素研究 总被引:1,自引:1,他引:0
华北克拉通北缘~1.74Ga大庙斜长岩杂岩体赋含有大型Fe-Ti-P矿床。采用分步加热质谱法分别测定了块状Fe-Ti矿石、块状Fe-Ti-P矿石和浸染状矿石中磁铁矿、磷灰石和斜长石释出的挥发份组成、含量以及C-H-O同位素组成。依据矿物的释气总量变化特征将释气过程分为三个阶段:200~400℃、400~800℃和800~1200℃。根据不同类型矿石中矿物在不同释气阶段的挥发份组成、含量以及C-H-O同位素组成,可将含矿岩体中的流体类型分成四种:(1)斜长石800~1200℃阶段释出的变质流体,主要以H2O、N2+CO和CO2为主;(2)斜长石400~800℃阶段释出的幔源流体组分,主要以H2O、H2、CH4和CO2为主;(3)磁铁矿400~800℃阶段释出的地表流体,主要以H2O、CO2、SO2和H2S为主;(4)所有矿物200~400℃阶段释出的代表后期次生包裹体的组分,以H2O和CO2为主。矿石中的磁铁矿相对富集H2O和CO2等流体组分,是在相对氧化的条件下结晶的;而斜长石释出气体中H2和CH4的含量较高,是在相对还原的环境中结晶的。这反映出斜长石可能是在岩浆早期相对还原的条件下结晶的,而磁铁矿是在岩浆演化晚期相对氧化的条件下结晶的,这一过程的转变可能与岩浆演化晚期,岩浆中的挥发份逐渐聚集以及地表流体的加入有关。岩浆中H2O和CO2等流体含量的不断增加导致岩浆的氧逸度逐渐升高,最终造成磁铁矿的大量结晶并富集成矿。 相似文献
403.
The mineralogy of arsenic in uranium mine tailings at the Rabbit Lake In-pit Facility, northern Saskatchewan, Canada 总被引:3,自引:2,他引:3
A detailed investigation of the mineralogy of As in the tailings of the Rabbit Lake uranium ore processing facility was conducted.
The milling/ore extraction process was sampled at three different locations to obtain information about when, where and under
what condition secondary As phases form. These samples were compared with four samples of varying As content from the Rabbit
Lake in-pit tailings management facility (TMF). Up to 20% As in the tailings are present in primary minerals that reach the
tailings directly because they are not dissolved during the uranium extraction. The remaining 80% constitute As that was dissolved
during ore extraction and then re-precipitated before being discharged into the tailings pond. It was not possible to conclusively
identify any individual re-precipitated (secondary) As minerals in the Rabbit Lake TMF. Indirect evidence from sequential
extraction analyses suggests the presence of an amorphous Ca-As phase and a possible, but unlikely, minor amount of an amorphous
Fe-As phase. However, the close association between hydrous ferric oxide (HFO) and As could be clearly demonstrated. HFO was
identified to be 2-line ferrihydrite and its XRD pattern geometry indicates a substantial amount of adsorbed As. This is in
good agreement with SEM, TEM and sequential extraction analyses that all showed the close association of HFO and As.
Received: 14 February 2000 · Accepted: 9 May 2000 相似文献
404.
Abstract: The gold content in siliceous deposits formed from geothermal waters at the Hatchobaru geothermal power station in central Kyushu, Japan, was determined by inductively coupled plasma quadrupole mass spectrometry (ICP–MS). It ranges from 1.3 to 4.6 mg/kg. The highest gold content was obtained from the siliceous deposit formed from acidic waters. In this siliceous deposit, hydrous iron(III) oxide of amorphous state is a major constituent, suggesting that hydrous iron(III) oxide might play an important role when gold is concentrated into siliceous deposits formed from acidic and iron-rich geothermal waters. 相似文献
405.
Andrew O. Langford Paul D. Goldan Fred C. Fehsenfeld 《Journal of Atmospheric Chemistry》1989,8(4):359-376
An automated molybdenum oxide annular denuder system (MOADS) has been developed for gas phase ambient ammonia measurements. This system combines high sensitivity (detection limit <50 pptv) with continuous sampling, moderate collection times (30 min) and automated operation. The present denuder design confers two important advantages over the tungsten oxide coated quartz denuder tubes used previously for nitric acid and ammonia measurements. First, the present denuders use oxidized metal substrates and are easier to fabricate and more durable than denuders made from metal oxide coated glass or quartz tubes. Second, molybdenum (VI) oxide surfaces are used which oxidize a reproducible fraction of the adsorbed NH3 directly to NO upon desorption eliminating the need for a secondary catalytic converter. Laboratory tests of the collection/recovery characteristics of annular denuders made from both the (IV) and (VI) oxides of tungsten and molybdenum are described and preliminary results from field tests are presented. 相似文献
406.
407.
电感耦合等离子体发射光谱法测定稀土矿石中的三氧化二铝 总被引:1,自引:1,他引:0
铝是稀土矿石常检的杂质元素,目前采用电感耦合等离子体发射光谱法(ICP-AES)基体匹配校正模式测定矿石中的铝量,对基体中铝的空白及基体量有一定的要求;且稀土矿石的品种很多,铝在其中的存在形式也较复杂,简单的酸溶很难彻底地将铝转入溶液中进行准确测定.本文采用碱熔法处理样品,滤液酸化后用ICP-AES测定稀土矿石中的Al2O3.通过共存元素干扰实验发现样品中的稀土元素及钍对铝的测定产生严重的光谱干扰,提出预先以碱分离除去消除干扰,有效地降低了检测下限:采用基体校正模式,消除了盐分对测定的影响.方法检出限为0.021~0.035 mg/g,测定范围为0.50% ~ 8.00%,精密度(RSD)<7.1%.对不同含量的样品进行分析,测定值与化学容量法测定结果基本相符.该方法具有测定含量范围宽、分析速度快、结果准确等优点. 相似文献
408.
通过分析湖南、浙江和福建三省不同氧化铁和有机质含量共253个土样的光谱数据,研究了氧化铁对有机质光谱特征及定量反演的影响。结果表明:氧化铁的光谱特征波段为600—1400 nm;氧化铁含量小于20 g/kg时对有机质的光谱信息没有影响,含量在20—30 g/kg时,对有机质可见光波段光谱信息的表现有影响,近红外波段的影响不大,含量大于30 g/kg时,氧化铁会掩盖有机质的光谱信息;氧化铁与有机质的比值小于0.726时对有机质的光谱信息没有影响,比值为1.05—2时,对有机质400—1300 nm波段光谱信息的表现有影响,1300—2400 nm波段的影响不大,比值大于2.21时,氧化铁会完全掩盖有机质的光谱信息;氧化铁对有机质的光谱定量反演有影响,随氧化铁含量的增加或氧化铁含量与有机质含量比值的增大,模型的稳定性与预测能力有所降低,但氧化铁含量小于20 g/kg、氧化铁含量与有机质含量比值小于2.0时,氧化铁的影响不明显。 相似文献
409.
1 INTRODUCTION Nitric oxide (NO), a highly free radical gas, is recently discovered as messenger molecule involved in different cellular and developmental events including cell proliferation, differentiation and apoptosis as well as neural pathfinding and synapse formation. NO is synthesized from amino acid L-arginine by catalytic action of a family of isoen-zymes called nitric oxide synthases (NOS) (Palmer, 1988). NOS require nicotinamide adenine dinucleo-tide phosphate (NADPH) as a… 相似文献
410.