Comparison Method for Neutron Activation Analysis with γ-γ Matrix

A comparison method, utilizing neutron activation analysis followed by multidimensional spectrum analysis was proven to provide accurate quantification of the multi-element samples. In this study, 23 elements were detected simultaneously in a sample containing standard elements for neutron activation analysis. The method presented here can be applied for about 50 elements.     

Honey as an environmental indicator: Effect of sample preparation on trace element determination by ICP-AES

Trace element concentrations in honey collected from a wide area can be used as an environmental indicator, but sample preparation methods prior to analysis can have large effects on the results. The efficiency and reproducibility of sample preparation methods (dilution, ashing and digestion) for simultaneous multi-element analysis have been compared for 13 elements. Digestion in a PTFE bomb was found to be the most reliable method.     

Atomic fluorescence analysis with gas-phase atomization in an inductively coupled plasma

A method of analysis is proposed that involves isolation of elements to be determined from a sample in the form of volatile compounds, with their subsequent trapping and final atomic fluorescence determination with gas-phase atomization in an inductively coupled plasma. An air-cooled torch with a low consumption of argon was used as the atomizer. This technique eliminates almost all interferences from both matrix elements and atomizing media, and allows the analysis of a wide range of materials with a spectrometer that is calibrated on pure compounds of the elements to be determined without the need for matrix-matched standard reference materials. The method was applied to multi-element environmental analyses.     

Fast sequential multi-element determination of major and minor elements in environmental samples and drinking waters by high-resolution continuum source flame atomic absorption spectrometry

The fast sequential multi-element determination of 11 elements present at different concentration levels in environmental samples and drinking waters has been investigated using high-resolution continuum source flame atomic absorption spectrometry. The main lines for Cu (324.754 nm), Zn (213.857 nm), Cd (228.802 nm), Ni (232.003 nm) and Pb (217.001 nm), main and secondary absorption lines for Mn (279.482 and 279.827 nm), Fe (248.327, 248.514 and 302.064 nm) and Ca (422.673 and 239.856 nm), secondary lines with different sensitivities for Na (589.592 and 330.237 nm) and K (769.897 and 404.414 nm) and a secondary line for Mg (202.582 nm) have been chosen to perform the analysis. A flow injection system has been used for sample introduction so sample consumption has been reduced up to less than 1 mL per element, measured in triplicate. Furthermore, the use of multiplets for Fe and the side pixel registration approach for Mg have been studied in order to reduce sensitivity and extend the linear working range. The figures of merit have been calculated and the proposed method was applied to determine these elements in a pine needles reference material (SRM 1575a), drinking and natural waters and soil extracts. Recoveries of analytes added at different concentration levels to water samples and extracts of soils were within 88–115% interval. In this way, the fast sequential multi-element determination of major and minor elements can be carried out, in triplicate, with successful results without requiring additional dilutions of samples or several different strategies for sample preparation using about 8–9 mL of sample.     

Use of PIXE analysis to determine trace metals in drinking water in Jordan

The procedure for using proton induced X-ray emission (PIXE) in conjuction with the method of spotting for qualitative and quantitative multi-element analysis of drinking water in eight cities of Jordan is discussed in this article. It is likely that this method of preconcentration can be directly incorporated into field sampling procedures, thus eliminating the problems of sample contamination or trace element losses by absorption on container walls, the significance of some of the elements found in the samples is discussed.     

浅谈中药中微量元素的系统研究

提出了中医药微量元素系统研究的新思考．主要是在中医药理论的指导下一对中层中药的微量元素进行全面系统研究．在进行系统研究时,要做到以多元素、多因素分析为主．必须加强对样品前处理的研究及进行测定的质量控制等．     

电感耦合等离子体质谱法检测氧化镓中杂质元素

建立了电感耦合等离子体质谱法(ICP-MS)测定氧化镓中杂质元素的检测方法,采用微波消解技术溶样,以5 ng/mL Rh为内标补偿校正镓基体的抑制效应,采用碰撞室技术(CCT)消除多元素分子离子的干扰.方法的检出限为0.10～1.0 ng/mL,加标回收率在85%～110%之间,RSD为0.6%～7.1%.该方法能满足99.95%～99.995%氧化镓中杂质元素的分析要求.     

激光剥蚀-电感耦合等离子体质谱研究富钴结壳生长环带的元素分布

建立了以Ti为内标,富钴结壳标准物质GSMC-1为外标,193nmArF准分子激光剥蚀ICP-MS方法研究富钴结壳不同结壳层中元素组成及分布。所建立的定量方法用于GSMC-2和GSMC-3的测定,分析结果的相对标准偏差和相对误差均小于10%;各分析元素的检出限为3.2～191ng/g(除Si外),可以满足富钴结壳原位微区分析的要求。对取自西太平洋麦哲伦海山区富钴结壳样品MDD-42,从核心到最外结壳层以0.5mm的微间距剥蚀并采集140个样品点,不同生长环带的微区分析结果表明,成矿元素和伴生元素在不同结壳层中呈现不同的分布特性,直接反映了结壳形成时期的地质作用和古海洋沉积环境。     

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.     

Trace elements determination in red and white wines using total-reflection X-ray fluorescence

Several wines produced in different regions from south of Brazil and available in markets in Rio de Janeiro were analyzed for their contents of elements such as: P, S, Cl, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb and Sr. Multi-element analysis was possible with simple sample preparation and subsequent analysis by total-reflection X-ray fluorescence using synchrotron radiation. The measurement was carried at the X-ray fluorescence beamline in the Synchrotron Light Source Laboratory in Campinas, Brazil. The levels of the various elements obtained were lower in the Brazilian wines than the values generally found in the literature. The present study indicates the capability of multi-element analysis for determining the contents of various elements present in wines coming from Brazil vineyards by using a simple, sensitive and precise method.     

Investigation of element distribution and homogeneity of TXRF samples using SR-micro-XRF to validate the use of an internal standard and improve external standard quantification

Total reflection X-ray fluorescence analysis (TXRF) offers a nondestructive qualitative and quantitative analysis of trace elements. Due to its outstanding properties TXRF is widely used in the semiconductor industry for the analysis of silicon wafer surfaces and in the chemical analysis of liquid samples. Two problems occur in quantification: the large statistical uncertainty in wafer surface analysis and the validity of using an internal standard in chemical analysis. In general TXRF is known to allow for linear calibration. For small sample amounts (low nanogram (ng) region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. For higher total amounts of samples deviations from the linear relation between fluorescence intensity and sample amount can be observed. This could be caused by the sample itself because inhomogeneities and different sample shapes can lead to differences of the emitted fluorescence intensities and high statistical errors. The aim of the study was to investigate the elemental distribution inside a sample. Single and multi-element samples were investigated with Synchrotron-radiation-induced micro X-ray Fluorescence Analysis (SR-μ-XRF) and with an optical microscope. It could be proven that the microscope images are all based on the investigated elements. This allows the determination of the sample shape and potential inhomogeneities using only light microscope images. For the multi-element samples, it was furthermore shown that the elemental distribution inside the samples is homogeneous. This justifies internal standard quantification.     

Determination of bromine, chlorine, sulphur and phosphorus in peat by X-ray fluorescence spectrometry combined with single-element and multi-element standard addition

Bromine (20-40 ppm), chlorine (200-500 ppm), sulphur (0.2-3%) and phosphorus (300-1000 ppm) in peat have been determined by X-ray fluorescence spectrometry (XRFS) combined with the standard-addition method. Chlorine, sulphur and phosphorus have also been determined by other methods and agreement between the results is good. Theoretical calculations based on the Sherman equation were made to validate the linearity of the standard-addition curves. A multi-element standard-addition technique has been tested with addition of all elements at the same time. The results for chlorine were high but after correction for the difference in attenuation coefficient between the sample and added compound the results agreed with those from single-element standard addition.     

Direct determination of traces of Ag, Cd, Pb, Bi, Cr, Mn, Co, Ni, Li, Be, Cu and Sb in environmental waters and geological materials by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman-effect background correction

A method was developed for direct determination of minor and trace amounts of Cr, Mn, Cu, Ni, Co, Li, Pb, Cd, Bi, Sb, Be and Ag in silicate rock, lake and stream sediments using a microwave oven dissolution method and a multi-element graphite furnace atomic absorption spectrometer equipped with a Zeeman-effect background correction device. The measurement technique was also suitable for direct determination of trace and ultra-trace amounts of these elements in drinking and seawater samples. A rock or sediment sample was brought into solution in a Teflon vessel by heating in a microwave oven with a mixture of hydrofluoric acid and aqua regia, followed by a further heating with a mixture of boric acid and ethylenediaminetetraacetic acid. The specified elements were directly determined in a group of four elements in one firing and eight elements in two firings from this solution or from a diluted solution using the optimum operating parameters developed in this work. The method, tested with 23 international reference rocks and sediments and seven international quality control and reference water samples, showed good to excellent agreement with the recommended values.     

Multi-element analysis of airborne particulate matter by various spectrometric methods after microwave digestion

A microwave digestion procedure in combination of the measurement of various spectrometric methods including atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry was developed for the multi-element analysis of airborne particulate matter collected on PTFE filters by a dichotomous sampler. In order to achieve more sensitive and rapid multi-element analyses, special PTFE-lined digestion vessels were used. It was found that complete digestion of airborne particulates with an acid mixture of HNO₃-HClO₄-HF (3:7:1, v/v) can be achieved in the microwave-irradiated closed vessel system and direct spectroscopic measurement of the digested sample after appropriate dilution. A recovery study was conducted using a multi-element standard and NIST Standard Reference Material 1648 Urban Particulate. Sixteen major, minor, and trace elements in airborne particulate matter were determined.     

电感耦合等离子体发射光谱(ICP-OES)法测定水泥熟料中铬的干扰研究

电感耦合等离子体发射光谱法（ICP-OES）测定重金属时常面临干扰问题。为提高ICP-OES测定水泥熟料中铬的准确度,研究选取了Cr205.560、Cr267.716和Cr283.563三条谱线,根据水泥熟料中主量元素（铁、铝、钙和镁）含量,设计不同浓度单元素干扰试验,结果表明：铁对Cr283.563谱线测定有较大的正干扰,钙对三条谱线均有较大的负干扰,两者导致的相对误差（RE）均在±10%以上,其他一般为负干扰,RE在±10%以内。进一步线性回归分析发现,除铝外,其他干扰元素的干扰大小与浓度呈强线性相关性。通过多元素复合干扰试验发现干扰导致的RE约为-18%~11%,同单元素干扰加和结果比较,两者相差约为8%~10%。实际样品检测结果表明实际干扰同多元素复合干扰试验基本相同,Cr283.563谱线测定结果误差可能更小,三条谱线的实际样品加标回收率大致相当,约为80%,经回收率修正,Cr205.560和Cr267.716谱线结果满意,而Cr283.563谱线误差较大。以多元素复合干扰试验溶液作为基体,采用基体匹配法测定可基本消除干扰影响。以钙溶液作为基体的简化基体匹配法同样有效,但仅可选用Cr205.560和Cr267.716谱线。本研究从实际干扰问题出发,通过系统分析问题,找到干扰的原因,并据此提出消除干扰方法,提高了测定铬的准确度,也为检测人员解决相关干扰问题提供借鉴。     

Determination of noble metals in silicate rocks, ores and metallurgical samples by simultaneous multi-element graphite furnace atomic absorption spectrometry with Zeeman background correction

A new method has been developed for rapid determination of mug/g and ng/g amounts of noble metals in silicate rocks, ores and metallurgical samples by attacking with hydrofluoric acid and aqua regia, preconcentration by ion-exchange chromatography and measuring in a simultaneous multi-element graphite furnace atomic absorption spectrometer equipped with a polarized Zeeman background correction device which eliminated interferences from any incompletely separated common elements. The method was tested for Ru, Rh, Pt, Ir, Pd, Ag and Au with three Canadian certified reference materials, and then applied to the determination of ng/g amounts of these elements in four new Canadian candidate reference materials.     

XRF and TXRF techniques for multi-element determination of trace elements in whole blood and human hair samples

XRF and TXRF were established as useful techniques for multi-element analysis of whole blood and human head hair samples. Direct-XRF with different collimation units and different X-ray excitation modes was successfully used for the determination of S, P, K, Ca, Fe, and Br elements in blood samples and K, Ca, Mn, Fe elements in human hair samples. Direct analysis by TXRF was used for the determination of Rb and Sr in digested blood and human hair samples, respectively, while, the co-precipitation method using APDC for TXRF analysis was used for the determination of Ni, Cu, Zn, and Pb elements in both matrices. As a result, the improved XRF and TXRF methods were applied for multi-element determination of elements in whole blood and human hair samples in non-occupational exposed population living in Damascus city. The mean concentrations of analyzed elements in both matrices were on the reported range values for non-occupational population in other countries.     

Determination of rare earth elements in geological samples by inductively coupled plasma atomic emission spectrometry with flow injection liquid-liquid extraction.

A direct sampling with organic solvent extracts for simultaneous multi-element determination implemented with inductively coupled plasma atomic emission spectrometry (ICP-AES) associated with a flow injection liquid-liquid extraction (FI-LLE) sample preconcentration method was studied. The "robustness" of the plasma discharge with tributyl phosphate (TBP) loading was diagnosed by using the Mg II 279.55 nm and Mg I 285.21 nm lines intensity ratio. A FI-LLE preconcentration system for rare earth elements (REEs)-nitrate-TBP was established by using a laboratory-designed phase separator. For these elements, an average sensitivity enhancement factor of 64 was obtained with respect to ICP-AES sampling with aqueous solutions. The precision of the method was characterized by a relative standard deviation (%RSD) of 1.8 - 5.2%. A throughput of 27 samples per hour can be achieved with an organic solvent consumption of less than 200 microl per determination. Good results were obtained for the analysis of standard reference materials.     

Automated matrix separation and preconcentration for the trace level determination of metal impurities in ultrapure inorganic salts by high-resolution ICP-MS

A rapid and simple analytical method for the determination of transition metals and rare earth elements at sub-ng/g levels in alkaline and earth alkaline salt matrices was developed. Automated solid-phase extraction was utilized for matrix separation and analyte preconcentration from highly concentrated brine solutions. The HPLC system used was equipped with a chelation column packed with an iminodiacetate-based resin. Detection was accomplished by means of high-resolution inductively-coupled plasma mass spectrometry (ICP-MS), which allowed quasi-simultaneous multi-element determinations. A microconcentric nebulizer was employed for HR-ICP-MS to determine the elements of interest in small volumes of sample extracts. The method was shown to be very sensitive with limits of quantification in the range of 1–40 ng/g for all investigated elements. The method exhibited excellent precisions, high analyte recoveries, linear responses of least three orders of magnitude, high accuracy and low contamination susceptibility. A comparison of automated solid-phase extraction with methodologies utilizing traditional liquid-liquid extraction showed that the former offered similar analytical performance but was clearly easier to use and faster to perform, resulting in substantial time, labor and cost savings.     

Determination of wear metals in engine oil by mild acid digestion and energy dispersive X-ray fluorescence spectrometry using solid phase extraction disks

A simple, particle size-independent spectrometric method has been developed for the multi-element determination of wear metals in used engine oil. A small aliquot (0.5 ml) of an acid-digested oil sample is spotted onto a C-18 solid phase extraction disk to form a uniform thin film. The dried disk is then analyzed directly by energy dispersive X-ray fluorescence spectrometry. This technique provides a homogeneous and reproducible sample surface to the instrument, thus overcoming the typical problems associated with uneven particle size distribution and sedimentation. As a result, the method provides higher precision and accuracy than conventional methods. Furthermore, the disk sample may be stored and re-analyzed or extracted at a later date. The signals arising from the spotted disks, and the calibration curves constructed from them, are stable for at least 2 months. The limits of detection for Fe, Cu, Zn, Pb, and Cr are 5, 1, 4, 2, and 4 μg g⁻¹, respectively. Recoveries of these elements from spiked oil samples range from 92 to 110%. The analysis of two standard reference materials and a used oil sample produced results comparable to those found by inductively coupled plasma atomic emission spectrometry.