Determination of arsenic in geological samples by HG AAS

A continuous hydride generation (HG) AAS procedure for the determination of As in geological samples utilizing the SH-group containing amino-acid L-cysteine for the pre-reduction of As(V) to As(III) in HNO₃ has been optimized and compared with a method utilizing KI and ascorbic acid in HCl. The influence of some transition metals (Co, Fe, Ni) on the determination of As has been investigated. Decompositions of geological certified reference materials, sediments and soils of different origin and geochemical composition with concentrated HNO₃ have been performed in open and closed systems and the resulting As content has been compared with certified and proposed data.     

Determination of arsenic in geological samples by HG AAS

A continuous hydride generation (HG) AAS procedure for the determination of As in geological samples utilizing the SH-group containing amino-acid L-cysteine for the pre-reduction of As (V) to As (III) in HNO(3) has been optimized and compared with a method utilizing KI and ascorbic acid in HCl. The influence of some transition metals (Co, Fe, Ni) on the determination of As has been investigated. Decompositions of geological certified reference materials, sediments and soils of different origin and geochemical composition with concentrated HNO(3) have been performed in open and closed systems and the resulting As content has been compared with certified and proposed data.     

Determination of talc in geological samples by infrared spectrometry

Talc is determined by infrared spectrometry in talc ore and mineral mixtures containing clinochlore chlorite, dolomite and magnesite as major minerals. When the Si-O-Si vibration at 668 cm^?1 is used, the calibration graph is linear up to about 0.5 mg of talc. Band overlap from chlorite is corrected by using the ratio of absorbances at 668 and 3620 cm^?1. Talc (?15%) in talc/carbonate/chlorite mixtures and ore was determined with relatively good precision and accuracy (recovery 91.2–97.4%). The sample sizes were 0.5–1 mg for 40–60% talc and 0.5–1.5 mg for 7.5–15% talc. The recoveries were worse (84.0–94.6%) for < 15% talc. The precision for unknown samples of talc ore varied from 1.5 to 4.0% (n=4).     

Determination of traces of rare earth elements in geological samples

A procedure for the determination of traces of rare earth elements by inductively coupled plasma-optical emission spectrometry (ICP-OES) and X-ray fluorescence spectrometry (XRF) is presented. The samples are decomposed either by fusion with lithium tetraborate or by acid attack in a microwave oven. Separation of the rare earth elements from accompanying elements is achieved by anion exchange. For the determination by ICP-OES the samples are injected in hydrochloric acid solution, for the determination by XRF the rare earth element traces are co-precipitated with rhodizonate and tannin and measured as a thin film on a membrane filter. All preconcentration steps have been optimized and tested using radiotracers. Furthermore the rare earth element contents of some international standard reference rocks have been determined; the results are compared to the certified values and other values given in the literature. The procedure is applied to a series of petrographically identical metabasites with different degrees of metamorphism to show the mobility of those ions under metamorphic conditions.     

Determination of fluorine in geological samples using accelerator derived neutrons

A fast, neutron activation analysis technique is described for the determination of fluorine in geological samples. The method utilises the reaction¹⁹F(n,α)¹⁶N for the determination. However, it avoids the interference reaction from oxygen which produces the same radionuclide since the neutrons are derived from the bombardment of beryllium with 3 MeV deuterons. The maximum energy of the neutrons so produced is well below the threshold for the competing oxygen reaction. The results indicate that the method gives acceptable accuracy over the range of a few tens ppm to several percent fluorine content using suitable standards. Sample analysis time is only a few minutes allowing the analyses of large numbers of samples per day.     

X射线荧光光谱法测定地质样品中的硫和氟

采用粉末压片制样-X射线荧光光谱法研究地质样品中硫(S)和氟(F)元素的快速测定方法。通过分级过筛实验优化确定样品粒度,探讨样品粒度对测定结果的影响,并进行实际样品和标准物质验证。结果显示,样品粒度为85μm时,经实际样品和标准物质验证,测定结果与化学值和标准认定值相符,且相对标准偏差(RSD)均小于2%。方法具有准确度高、检出限好、测试范围宽、简便快速等优点,能确保样品分析结果的准确性,实现了地质样品中S和F的快速测定。     

Determination of rare earths in geological samples by neutron activation analysis

The significance of rare earth distribution patterns in trace element geochemistry is briefly reviewed. Established methods for their determination at the Reactor Centre by instrumental and radiochemical techniques are described, and examples of recent applications discussed.     

电感耦合等离子体质谱测定地质样品中多种元素

用电感耦合等离子体质谱(ICP-MS)测定了地质样品中多种元素。考察了测量过程中的基体效应及质谱干扰,利用In内标,补偿由于基体效应的影响所引起的测量偏差,建立校正公式校正质谱干扰。方法的检出限为0.06~250ng/L,精密度为1.7%~3.2%,加标回收率为91%~108%,方法适于批量地质样品分析。     

Determination of 22 elements in geological samples by instrumental neutron activation analysis

An instrumental neutron activation analysis (INAA) method has been developed for multi-element determination in geological samples. The INAA method consists of irradiation of samples for 90 sec at a flux of 1.0·10¹² n·cm⁻²·sec⁻¹ and determination of 12 elements by using their short-lived nuclides. Samples have been re-irradiated for 3 hrs for measuring concentrations of another 10 elements. Precision and accuracy of the INAA method have been evaluated by analysing samples and USGS standard reference materials. Precision and accuracy are within±15% and ±10%, respectively.     

螯合树脂微柱分离富集火焰原子吸收法测定地质样品中的痕量银

利用新合成的螯合树脂聚[4 乙烯苄基 (2 羟乙基硫醚)]制备微型吸附柱,采用螯合树脂微柱分离富集 火焰原子吸收法测定了地质样品中的痕量银。研究了螯合树脂微柱的吸附性能及影响吸附的因素,在稀王水介质中进行吸附,采用酸性硫脲为洗脱剂,以峰面积方式检测,测定Ag 的线性范围0.010～1.0μg mL,灵敏度提高40倍,吸附率在80%,相对标准偏差<4.2%,树脂柱可重复利用100次以上。     

Matrix sensitivity of solid sampling AAS. Determination of zinc in geological samples

Direct solid sampling techniques in AAS have several advantages over wet digestion methods such as small sample size requirements and simple calibration procedures. But some disadvantages also exist such as the sample in homogeneity and the matrix sensitivity of calibration. The calibration is commonly carried out by varying the sample mass and evaluating the peak intensity versus absolute analyte amount. It is shown here that this procedure must be considered doubtful when matrix effects are expected. In the case of zinc determination in geological samples it has been shown that calibration functions obtained by different reference materials differ significantly from each other. As an alternative a three-dimensional calibration technique can be applied that evaluates the peak intensity versus both analyte content and sample weight. The resulting calibration planes are expected to be hyperbolically curved. This three-dimensional calibration has been applied to the determination of Zn in geological samples and compared with classical solid sampling AAS calibration procedures.     

Determination of the sulphur content of geological samples by X-ray fluorescent analysis

Summary The sulphur content of ultramafic and basic rocks is determined by X-ray fluorescent analysis with pressed powder pellets. A commonly marked cellulose powder and wax are taken as diluent. Two analysing crystals, PET and graphite, are compared. The linear calibration curve reaches from 50 ppm to 1.0 weight-%, with a detection limit of 90 and 45 ppm, respectively. If the standard rock is of nearly the same matrix as the examined samples, no calculated matrix correction is necessary.

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Schwefelbestimmung in geologischen Proben durch Röntgenfluorescenz-Analyse

Zusammenfassung Eine Methode zur röntgenfluorescenzanalytischen Schwefelbestimmung an ultrabasischen und basischen Gesteinen wird beschrieben. Die Messung erfolgt an Preßtabletten mit handelsüblichem Cellulosepulver oder Wachs als Verdünnungsmittel. Zwei Analysatorkristalle, PET und Graphit, werden verglichen. Die lineare Eichkurve umfaßt den Konzentrationsbereich zwischen 50 ppm und 1 Gew.-% S. Die Nachweisgrenze liegt bei 90 bzw. 45 ppm, je nach verwendetem Kristall. Bei annähernd übereinstimmender Matrix von Standard- und Analysenprobe ist eine rechnerische Matrixkorrektur nicht erforderlich.

     

硫酸预加热-容量法测定含氯地质样品中的有机碳

氯离子的存在影响有机碳的测定,导致结果偏高。采用硫酸预加热-重铬酸钾氧化的溶矿体系处理样品,在预加热过程中氯离子转化为氯化氢挥发,消除了氯离子的干扰;恒温电热板消解样品,避免了油浴对样品及环境的污染。通过对氯离子干扰定量实验、预加热温度、预加热时间等条件进行探讨,确定了最佳实验条件。在不影响有机碳与重铬酸钾正常反应的前提下,有效地消除了氯离子对有机碳测定的干扰,实现了含氯地质样品中有机碳的准确测定。通过土壤标准物质、海洋沉积物等含氯国家标准物质进行验证,相对误差小于1.5%,相对标准偏差小于7.3%,结果重现性好,准确度高,且操作简便,对环境无二次污染,易于推广应用。     

Determination of Hf, Sc and Y in geological samples together with the rare-earth elements

 A method is described for the determination of Hf, Sc and Y simultaneously with the REE in geological materials. An earlier method for REE separation from major elements was studied with the aim to apply it also to the determination of Hf, Sc and Y. Sample decomposition was carried out by melting with LiBO₂. The method involves separation and concentration stages, using the cation-exchange resin DOWEX AG 50W-X8. Matrix elements were eluted with 2 mol/l HCl, whereas 6 mol/l HNO₃ with oxalic acid and 8 mol/l HNO₃ were used to elute the elements to be determined. Some of the matrix elements could not be completely removed. This effect as well as the recovery rates of the determined elements were investigated. The measurements were performed by ICP-AES. Spectral interferences were also tested. Received: 8 November 1995/Revised: 12 March 1996/Accepted: 14 March 1996     

Determination of gadolinium in geological samples by inductively coupled plasma mass spectrometry and multivariate calibration

Gadolinium can be difficult to determine by ICP-MS. In a normal geological sample there are risks of spectroscopic interferences on all of its isotopes. In this study this problem has been solved by using partial least squares (PLS) regression. Two PLS models are investigated: the first is based on aqueous standards, and the second on reference materials. Both models are capable of determining Gd with good results in reference materials containing interfering elements. It was not necessary to correct for nonspectroscopic matrix interferences. PLS is compared to principal components regression (PCR), another multivariate calibration method. For the aqueous standards PLS leads to a simpler model, while similar results are obtained for the two methods in the model based on reference materials.     

Determination of gold and the platinum group elements in geological samples by ICP-MS after nickel sulphide fire assay: difficulties encountered with different types of geological samples

Problems involved in the determination of Au and the platinum group elements by the nickel sulphide fire assay (NiS-FA) procedure for black shale samples, samples containing magnetite, and samples containing As, Cu, and Fe were studied. The interference of the graphite in black shale samples was eliminated either by roasting the sample prior to fusion or by adding an oxidant to the fusion flux. Addition of a reducing agent to samples, containing the oxygen-rich mineral magnetite, enabled the NiS-FA procedure to be carried out for this sample type. The interference of Cu on Rh in the ICP-MS determination was corrected by establishing a linear correlation between the interference of Cu on (103)Rh and (105)Pd.     

电沉积-钨丝电热原子吸收光谱法测定地质样品中痕量金

以市售幻灯投仪卤钨灯泡钨丝为原子化器的钨丝电热原子吸收光谱分析仪(TC-AAS),功率小、仪器成本低[1,2],如用微型CCD光谱仪作检测系统,可以实现原子吸收光谱仪的小型化,甚至可用于野外现场分析[3,4].     

电感耦合等离子体质谱(ICP-MS)法测定地质样品中Cu和Zn的干扰研究

电感耦合等离子体质谱(ICP-MS)法标准模式测定地质样品中Cu和Zn时,样品溶液中Ti在高温下易形成TiO⁺和TiOH⁺产生离子重叠干扰,使测定值偏离真值而影响测定结果。采用氢氟酸-高氯酸-硝酸消解、王水复溶样品,通过多级在线校正⁴⁶Ti¹⁶O⁺,消除TiO⁺和TiOH⁺离子重叠干扰,研究了单质Ti与⁴⁶Ti¹⁶O⁺、质荷比63、64、65、66离子间存在的关系,建立了一种电感耦合等离子体质谱(ICP-MS)法测定地质样品中Cu和Zn的分析方法。结果表明：单质Ti对Cu和Zn产生的干扰值与其质量浓度呈非简单的正相关性,TiO⁺产生的干扰离子质荷比65离子强度比63高,质荷比64离子强度比66高;⁴⁶Ti¹⁶O⁺对质荷比63、66离子干扰增量值与单质Ti质量浓度变化无关;^6...     

开叉毛细管HG-FAAS测定地质样品中的锑、铋

氢化物发生原子吸收法(HG-FAAS)广泛应用于冶金、地质、环境、医药和食品分析等领域中。研究表明,氢化物发生法的检出限、测定精度以及干扰等情况与原子化器和氢化物发生器的结构以及传输过程有关[1]。郭小伟等[2-4]研制了用于火焰原子吸收光谱分析的双毛细管喷雾器,并利用其测