Instrumental photon activation analysis of environmental materials using the internal standard method

In order to study effective applications of the photon activation analysis using the internal standard method, determinations of Cr, Co, Ni, Zn, As, Rb, Sr, Y, Zr, Nb, Sb, Cs, Ba, Ce and Pb in two marine sediments as environmental materials have been examined by the use of a personal computer-based gamma-ray spectrometer equipped with a micro-robot for sample changing. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards to check the roles with each other. As a result, it was demonstrated that accurate and precise determinations of the above 15 elements were achieved efficiently and favourably.     

Determination of ultratrace impurity elements in high purity niobium materials by on-line matrix separation and direct injection/inductively coupled plasma mass spectrometry

The determination of 52 impurity elements in niobium materials (niobium metal, niobium oxide (V), and niobium pentaethoxide) was performed by inductively coupled plasma mass spectrometry (ICP-MS) with on-line anion exchange matrix separation as well as direct nebulization. Niobium material samples were decomposed with a mixture of hydrofluoric acid and nitric acid to prepare 10% niobium solutions. In the on-line anion exchange matrix separation/ICP-MS, the niobium and hydrofluoric acid concentrations in sample solution were adjusted to 5% and ca. 8 M, respectively. The solution was then injected into the carrier stream from the sample loop of injection valve to pass through an anion exchange resin column. In the anion exchange separation, niobium in the fluoro-complex form was adsorbed on the resin, while impurity elements were eluted. The eluted elements were introduced into ICP-MS for the determination of 25 impurity elements. On the other hand, 27 impurity elements could not be separated well from niobium matrix under the above anion exchange conditions, and then the sample solution with the niobium concentration of max. 0.2% containing internal standard elements was injected from the sample loop of injection valve directly to introduce into ICP-MS. As a result, 52 impurity elements in three kinds of niobium materials could be determined at the ng g⁻¹ level.     

高分辨等离子体质谱法直接测定高纯镓中的痕量元素

建立高分辨电感耦合等离子体质谱法(HR-ICP-MS)测定高纯镓样品中Be、Mg、A l、S i、Ti、V、Cr、Mn、Fe、Co、N i、Cu、Zn、Ge、As、Mo、Ag、Cd、In、Sb、Ba、Pb、B i等痕量元素的方法。样品用HNO3 HC l经微波消解后,试液直接进样用HR-ICP-MS法同时测定上述元素,在高分辨质谱测量模式下避免了大量的质谱干扰,详细地研究了HC l和高纯镓所产生的基体效应,以Sc、Rh、Tl作为内标元素校正了基体效应,讨论和确定了实验的最佳测定条件。结果表明,23种痕量元素的检出限在0.001~0.21μg/L之间;回收率在89.8%~111.6%之间,相对标准偏差(RSD)小于3.3%。     

Determination of trace elements in residual oil by high-resolution inductively coupled plasma mass spectrometry

An analytical method using high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for rapid simultaneous determination of 20 elements, including Na, Mg, Al, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, and Pb elements, in residual oil was described. The sample was dissolved in HNO₃ by microwave digestion, and then the above 20 elements in the solution were analyzed directly by HR-ICP-MS. Most of the spectral interferences could be avoided by measuring in the high-resolution mode. The matrix effect caused by the sample-digesting solution and corrected by Sc, Rh, and Bi as the internal standard elements was studied in detail. The optimum condition of the determination was also tested and discussed. The result showed that the detection limits of the method were in the range of 0.014 to 11.6 μg L⁻¹; the relative standard deviation was less than 3.8% and recoveries in the samples were in the range of 88.4% to 108.0%. This method can be used to determine the trace elements in residual oil with the features of accurate, rapid, and convenient determination.     

电感耦合等离子体质谱法测定高纯金中铝、砷、铋、铬、铁、铅、锑、硒、碲、铱痕量元素

建立了微波消解-内标法-标准加入-ICP-MS法测定高纯黄金中铝、砷、铋、铬、铁、铅、锑、硒、碲、铱等痕量元素的分析方法.从试样溶解方式、内标元素及同位素的选择、仪器检测模式的优化及降低基体抑制效应等方面进行优化.实验加标回收率为99.5％ ～110％,相对标准偏差(RSD)为0.050％ ～6.5％.实验的准确度和精...     

Instrumental photon activation analysis of coal fly ashes using the internal standard method coupled with the standard addition method

Multielement determinations of coal fly ashes (NIST SRM-1633a and BCR CRM-38) have been carried out by instrumental photon activation analysis using 30 MeV bremsstrahlung and the internal standard method coupled with the standard addition method. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards. As a result, it was demonstrated that concentrations of 18 elements were determined accurately and precisely. Furthermore, a similar multielement determination has also been examined using 20 MeV bremsstrahlung. In this case, it was proved that better results can be achieved, because all interfering reactions were eliminated completely.     

Contributions to accuracy improvement of simultaneous ICP atomic emission spectrometry using multi-line measurements of analyte and internal standard elements Applications for the analysis of permalloy

For successful application of simultaneous ICP atomic emission spectrometry for major component determinations in multi-component materials the accuracy of the method has to be improved. As a contribution to solve this problem a combined procedure for multi-component standard sample preparation, optimum calibration and different variations of internal standard corrections is described. Variance-weighted multi-line calibrations give most accurate results. Internal standard corrections are effective, if the time-dependent spectral line intensity fluctuations of the standard and the analyte elements are well correlated. Their sensitivities against some responsible device parameter variations are investigated. On the basis of multi-line measurements of the analyte and internal standard elements a “group-selected internal standard correction” (GS-ISC) method is applied and results in relative errors of less than 1% even for extreme fluctuations of the raw intensities. For rapid routine determination methods of materials with variable element compositions the added line intensities of the internal standard element can be used to correct the added analyte line raw intensities (“intensity addition internal standard correction” (IA-ISC) method). These accuracy optimization procedures are applied for the analysis of the soft magnetic material permalloy using the internal standard element In.     

Total reflection X-ray fluorescence analysis of Mongolian coals

Coal samples were analysed for trace elements using total reflection X-ray fluorescence with monochromatic excitation. The procedure involved direct irradiation of the sample with the incoherent peak as internal standard. A new method for spectrometer sensitivity determination and sample quantification, was evaluated. Variable amounts of several trace elements were obtained in the analysis of coal from eight different deposits of Mongolia. The accuracy of the procedure was verified with the analysis of a coal standard.     

Multi-element analysis of urine by inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry

This work shows the analytical potential of inductively coupled plasma orthogonal-acceleration time-of-flight mass spectrometry (ICP-OA-TOF-MS) for rapid, simultaneous, and reliable determination of more than 50 elements at ultra-trace levels in urine. Under optimum instrumental conditions, after a 10-fold sample dilution step, and by using Rh as an internal standard, ICP-OA-TOF-MS also enables the determination of elements whose assay is more diffcult when using conventional quadrupole instruments. This is confirmed by the analysis of commercially available reference urine samples and/or by analytical recoveries study and isotope ratio based determination of accuracies. On the other side, the interference resulting from polyatomic carbon, chlorine, or various sulfur species does not allow the determination of elements such as Cr, Fe, V, Se and As without a mathematical correction.

The search for internal isotopic tracers in metallurgical materials

In a search for internal isotopic tracers in metallurgical materials a group of elements has been chosen which can be determined by the neutron activation method with the higher sensitivity. A method has been developed for the determination of W, As, Au, La, In, Sc, Re and Ir in metallurgical materials. The separation of the elements was carried out using extraction and precipitation. The determination of the elements was carried out in samples of chamotte brick and washed ores. The limits of the determination of the elements are of the order of 10⁻¹¹ g for Au, 10⁻¹⁰ g for In and La and 10⁻⁹ g for As, W, Sc, Re and Ir. The large scatter of the results indicates the inhomogeneity of the materials analyzed.     

电感耦合等离子体质谱法测定汽油中微量元素的研究

为建立电感耦合等离子体质谱(ICP-MS)测定汽油中V、Mn、Fe、Co、Ni、Cu、As、Pb等微量元素的分析方法,样品用HNO3微波消解后,试液直接用ICP-MS法测定,详细讨论了仪器工作参数、样品基体的干扰,以Sc、Re作为内标物质,补偿了基体效应,选择适当的待测元素同位素克服了质谱干扰,确定了实验的最佳测定条件。结果表明,8种微量金属元素的检出限在0.001~0.015μg/L之间;线性关系良好,线性相关系数r≥0.999 9;精密度良好,RSD2.78%;回收率在94.0%~106.0%之间;该法准确、快速、简便,应用于汽油中微量元素的测定,结果满意。     

Highly accurate and precise multielement determination of environmental samples by means of photon activation using the internal standard method

In order to examine effective applications of the newly developed internal standard method, determinations of Cr, Co, Ni, Zn, As, Rb, Sr, Y, Zr, Nb, Cs, Ce and Pb in three environmental materials, such as pond, lake and estuarine sediments, have been tried by means of photon activation. In these examinations, some major constituent elements in the above sediments were properly used as excellent and effective internal standards. In consequence, it was confirmed that highly accurate and precise determinations of the above 13 elements were achieved easily and favourably.     

微波消解-电感耦合等离子体质谱(ICP-MS)法测定稀释沥青中23种元素

稀释沥青是一种中间产品,主要用于生产沥青。目前稀释沥青中元素含量的测定方法较少,前处理过程繁琐。本文采用微波消解-电感耦合等离子体质谱法同时测定稀释沥青中铝、钒、铬、锰、铁、钴等23种元素,对研究稀释沥青各元素组成,具有重要意义。通过选择合适的前处理方式,最终采用微波消解稀释沥青,优化样品称样量、消解试剂、赶酸温度,通过引入内标元素对非质谱干扰进行校正,通过调谐优化仪器参数、碰撞反应池He模式、干扰方程、选择合适同位素等手段对质谱干扰进行了校正。样品进行测定时采用45Sc、72Ge、115In、209Bi作为内标元素,对方法的检出限、精密度、准确度等进行考察。在优化的试验条件下,23种元素在一定的质量浓度范围内与其信号强度呈线性关系,标准曲线线性良好,相关系数在0. 9990~1.0000之间,方法的检出限在0.0005~1.02mg/kg之间,方法用加标回收测定回收率,回收率范围在80.0~110.5%之间,对稀释沥青样品平行测定7次,测定值的相对标准偏差在0.47~3.09%之间。利用该方法对进口稀释沥青进行23种元素进行测定,满足国家标准对各项技术指标参数的要求,检出限低,选择性好,结果准确可靠,为稀释沥青类样品中多种元素分析测定提供了新的参考方法。     

Internal standard method for determination of gallium and some trace elements in bauxite by neutron activation analysis

A method is described for the determination of gallium and other trace elements such as Ce, Cr, Hf, Lu and Th in bauxite by the technique of neutron activation analysis using gold as internal standard. Isopropyl ether was used as organic extractant to extract radioactive gallium from the sample. This method yields very good accuracy with a relative error of ±3%.     

Determination of trace elements and correction of mass spectral interferences in superalloy analyzed by glow discharge mass spectrometry

Mass spectral interference was investigated systematically during the determination of trace elements in superalloy by glow discharge mass spectrometry (GD-MS); moreover the main mass spectral interference and interference level of isotopes were provided in detail. According to the mass spectral interference of elements, different methods were selected for interference correction. The effects of mass spectral interference were removed efficiently by using correction methods such as selecting isotopes without interference, matching sample matrices and deducing interference with multivariable linear regression. The determination results of three superalloy samples show that trace elements such as B, Mg, Ga, As, Ag, In, Sn, Sb, Te, Tl, Pb and Bi were determined successfully after interference correction.     

Revaluation of the internal standard method coupled with the standard addition method applied to soil samples by means of photon activation

In order to achieve the highly accurate and precise multielement determination in environmental materials, the usefulness of the comparative standard provided by the processing method proposed previously for soil samples has been re-examined using calcareous loam soil, light sandy soil and river sediment as unknown samples. As a result, it was also demonstrated that concentrations of 15 trace elements in each sample can be determined effectively and reasonably.     

A comparison of the performance of a fundamental parameter method for analysis of total reflection X-ray fluorescence spectra and determination of trace elements,versus an empirical quantification procedure

The performance has been compared of two different quantification methods — namely, the commonly used empirical quantification procedure and a fundamental parameter approach — for determination of the mass fractions of elements in particulate-like sample residues on a quartz reflector measured in the total reflection geometry. In the empirical quantification procedure, the spectrometer system needs to be calibrated with the use of samples containing known concentrations of the elements. On the basis of intensities of the X-ray peaks and the known concentration or mass fraction of an internal standard element, by using relative sensitivities of the spectrometer system the concentrations or mass fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass per unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements to be determined are calculated during fitting a modelled X-ray spectrum to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross-sections of a peat core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi-element standard solution.     

An internal standard method for the determination of trace elements in cigarette tobacco by neutron activation analysis

An internal standard method has been applied for the determination of lanthanum, antimony, scandium, chromium, iron and cobalt in commercial cigarettes by neutron activation analysis using gold as an internal standard element. These trace elements were separated from irradiated samples by APDC (ammonium pyrrolidine dithiocarbamate)/Zeph (tetradecyl dimethyl benzyl ammonium chloride) coprecipitation, followed by direct gamma-counting of the separated precipitate using a Ge(Li) detector. Standard reference tobacco 1R1 prepared by the University of Kentucky was also analyzed by this procedure for the above 6 elements, the results of which were compared with literature values. Good results were obtained by the present method.     

Total reflection X-ray fluorescence analysis of fly ash from Bulgarian coal-fired power plants

The contents of Cl, Ca, K, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Ba and Pb in raw coal fly ash from five Bulgarian power plants were determined by total reflection X-ray fluorescence (TXRF), using gallium as the internal standard. The samples were analysed as in slurry form in Triton? X-114. The experimental parameters, such as grain size, concentrations of fly ash slurry and excitation time were optimised. For validation of the method, the certified reference material BCR-176R fly ash was used. The precision of the results obtained is characterised by a relative standard deviation of approximately 10%. The resulting data confirm the suitability of TXRF for the simultaneous determination of major, minor and trace elements in coal fly ash samples. Further advantages provided by TXRF are easy sample preparation (no sample dissolution) and the small sample amount required for analysis.     

Determination of Cr,Fe, Co,Ni, Cu,Zn, As and Pb in liquid chemical waste by energy dispersive X-ray fluorescence

A method for simultaneous determination of Cr, Fe, Co, Ni, Cu, Zn, As e Pb in liquid chemical waste using Energy Dispersive X-Ray Fluorescence (EDXRF) technique was evaluated. A small sample amount (200 μL) was dried on a 6.35 μm thickness Mylar film at 60 °C and the analyses were carried out using an EDXRF spectrometer operated with an X-ray Mo tube (Zr filter) at 30 kV/20 mA. The acquisition time was 300 s and the Ga element was utilized as internal standard at 25 mg/L for quantitative analysis. The method trueness was assessed by spiking and the detection limit for those elements ranged from 0.39 to 1.7 mg/L. This method is notable because it assists the choice of the more appropriated waste treatment procedure, in which inter elemental interference is a matter of importance. In addition, this inexpensive method allows a non-destructive determination of the elements from ₁₉K to ₉₂U simultaneously.