Highly accurate analysis of soft magnetic alloys by automated sample digestion and simultaneous ICP-OES

A study has been made of the feasibilities of automatic microwave-heated acid digestion and simultaneous inductively coupled plasma optical emission spectrometry (ICP-OES) for highly accurate analysis of soft magnetic alloys. The results of the analysis of a nanocrystalline soft magnetic alloy for Fe, B, Si, Cu and Nb were compared to those obtained by the classical chemical analysis methods. It can be shown that the automated digestion and simultaneous ICP-OES fulfil the accuracy requirements in most cases. Moreover, it is demonstrated that the analysis by automated digestion and simultaneous ICP-OES is considerably faster and has a reduced chemical consumption.     

超级微波消解-电感耦合等离子体发射光谱（ICP-OES）法测定土壤中18种元素

为提高土壤多元素同时检测的效率,采用超级微波消解-电感耦合等离子体发射光谱法测定土壤中钾、钠、钙、镁、铜、铁、锰、锌、磷、硫、硼、砷、镉、铬、铅、钴、镓、锂等18种元素含量。比较了超级微波消解、常规微波消解和电热板消解的处理效果,采用超级微波消解法对样品进行前处理,并优化了消解条件。在最优条件下,各元素的检出限在0.05~20 mg/kg,加标回收率在86.2%~107.5%,RSD在0.1%~3.0%,方法准确度及精密度可以满足多元素同时测定的需求,且该方法具有简单、快速、成本低、用酸量少、重现性好等特点。     

Improved accuracy for the analysis of soft magnetic alloys by inductively-coupled plasma atomic emission spectrometry by using advanced standardization procedures

The applicability of simultaneous ICP-OES for the accurate analysis of soft magnetic alloys has been investigated. Long-time signal variations of up to 40% can be observed under normal operating conditions. The scattering of the values can largely be compensated by a correction procedure with internal and external standardization where the intensity value of the analytical signal is first rationed to the simultaneously measured intensity of an internal standard line and after that recalibrated with an external standard. Not only the trueness but also the precision could be improved by using Cd as a real-time internal standard. This is attributed to a compensation for instrumental fluctuations as a result of the simultaneous measurement of both emission signals.     

Improved accuracy for the analysis of soft magnetic alloys by inductively-coupled plasma atomic emission spectrometry by using advanced standardization procedures

The applicability of simultaneous ICP-OES for the accurate analysis of soft magnetic alloys has been investigated. Long-time signal variations of up to 40% can be observed under normal operating conditions. The scattering of the values can largely be compensated by a correction procedure with internal and external standardization where the intensity value of the analytical signal is first rationed to the simultaneously measured intensity of an internal standard line and after that recalibrated with an external standard. Not only the trueness but also the precision could be improved by using Cd as a real-time internal standard. This is attributed to a compensation for instrumental fluctuations as a result of the simultaneous measurement of both emission signals.     

电感耦合等离子体原子发射光谱法(ICP-OES)测定水系沉积物中6种重金属元素

建立了自动消解仪消解-电感耦合等离子体原子发射光谱法(ICP-OES)同时测定水系沉积物中Cu,Zn,Ni,Cr,Pb,Co 6种元素含量的方法。方法中6种元素的检出限为0.000 2~0.02mg/L,工作曲线的相关系数均大于0.999。方法经国家标准物质(GBW07361)验证,准确度和精密度均能达到环境监测分析的要求,为水系沉积物中重金属元素含量的测定提供了简单可靠的分析方法。     

Application of multivariate calibration for simultaneous determination of major and minor constituents in U3Si2 by WDXRF technique

The aim of this work was to implement and to validate the multivariate calibration for simultaneous determination of major and minor constituents in uranium nuclear fuel by WDXRF technique. The method is nondestructive and involves no chemical treatments thus is possible to perform fast chemical analysis and produces no hazardous waste. The precision and accuracy achieved are statistically comparable to others sensitive techniques like ICP-OES for impurities determination.     

Total-reflection X-ray fluorescence: An alternative tool for the analysis of magnetic ferrofluids

This work presents the first application of the total-reflection X-ray fluorescence (TXRF) to the compositional study of magnetic ferrofluids. With the aims of validating the best analytical conditions and also, limitations of the TXRF in the compositional study of these materials, an alternative empirical method, based in the use of angle-dependence TXRF (AD-TXRF) measurements, is proposed. Three kinds of ferromagnetic nanoparticles, with different morphologies, have been studied. The techniques of inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) have been used to validate the TXRF results. In contrast with the plasma techniques, the developed TXRF procedure need not of previous chemical acid digestion. Additionally, two procedures of magnetic nanoparticles synthesis, co-precipitation and laser-pyrolysis, have been checked for the contaminants trace metals Zn, Mn and Cr. It has been found that the method of laser-pyrolysis produces nanoparticles of higher purity.     

微波消解-ICP-OES法测定鲢鱼肌肉中的19种矿物元素

以硝酸和过氧化氢混合溶液为消解溶剂,利用微波消解法制备鲢鱼肌肉样品溶液,再应用全谱直读电感耦合等离子体发射光谱测定技术(ICP-OES),对鲢鱼肌肉中所含的矿物元素进行较为全面的定性定量分析。定性结果显示,鲢鱼肌肉中含有19种矿物元素,分别是K,Ti,Al,Ga,B,Ba,Ca,Cd,Cr,Cu,Fe,Mg,Mn,Na,P,Pb,S,Sr,Zn等。定量结果显示,ICP-OES定量分析线性范围宽,可达2个数量级以上;工作曲线线性相关系数在0.999以上;样品测定RSD值在0.44 % ~ 11.83 %之间,大部分在5%以内;除了一个元素以外,回收率测定结果都在(100±10)%以内;测定结果可为相关应用研究提供参考数据。     

Reaction-rate method for the determination of phosphorus in agricultural products

A new automated reaction-rate method for the quantitative determination of phosphorus in grains and feeds is presented. The chemical methodology has been investigated, resulting in a high analytical throughput with precise, accurate results. The phosphomolybdenum blue reaction is used for the reaction-rate determination. After digestion of the samples by the official AOAC block digestion procedure, automated instrumentation is used for precise and rapid combination of the reactants and transfer of the mixed solution to an automated spectrophotometer. The rate of formation of the product during 5 sec is automatically determined and compared with rates obtained for phosphorus standards to determine the phosphorus content of the sample. Relative standard deviations of about 0.3% are obtained and results for determinations of phosphorus in grains and feeds are accurate as indicated by comparison with the average obtained by all laboratories participating in the AAFCO check sample programme.     

Simple methods for characterization of metals in historical textile threads

Characterization of metal threads on historical textile materials is important for preservation of valuable cultural heritage. Obtained results dictate decisions on cleaning, conservation and restoration steps. The most important part of characterization is chemical analysis of originally applied materials, since this enables understanding the nature of chemical and physical degradation and determines the cleaning methods. Methods applied should be non-destructive and sensitive enough to detect trace elements in small sample amounts. The goal of this research was to describe the most useful procedures for fast and simple determination of specific metals of interest. Therefore we propose application of scanning electron microscopy equipped with EDS detector (SEM-EDS) for sample surface analysis and inductively coupled plasma-optical emission spectroscopy (ICP-OES) for chemical analysis of metals threads. For quality insurance reasons, a comparative method applied for chemical analysis was atomic absorption spectrometry (AAS). This combination of methods has proven to be very useful in analysis of historical samples, since SEM-EDS was a simple and non-destructive method which provided information on chemical composition of sample surfaces, while ICP-OES and AAS enabled the full insight into the average chemical composition of samples. Nevertheless, both ICP-OES and AAS were destructive methods which demanded dissolving of samples prior to the analysis. In this work nine different metal fibers collected from historical textile materials were characterized. Proposed methods enabled obtaining information on sample constitution, morphology, topology and chemical composition.     

电感耦合等离子体发射光谱法测定柑桔类水果及果皮中多种微量元素

采用HNO_3-HClO_4体系湿法消解样品,利用电感耦合等离子体发射光谱仪同时测定了柑桔类水果及果皮中Al、B、Ba、Ca、Cu、Fe、K、Mg、Mn、Na、Sr、Zn 12种微量元素的含量。分析结果的相对标准偏差0.35%~3.26%,加标回收率85.5%~107.0%,该法简单、快速、可靠、灵敏度高。实验表明,大部分柑桔类水果果皮中微量元素含量高于其果肉中含量。柚子内皮和外皮中微量元素含量有少许差异,柚子外皮中的K、Ca、Mg含量最高,而柚子内皮中Fe、Na的含量较高。该结果为有效利用柑桔类水果果皮的药用功效提供了定量参考依据。     

Pd–S-methylisothiourea supported on magnetic nanoparticles as an efficient and reusable nanocatalyst for Heck and Suzuki reactions

Supported Pd–S-methylisothiourea on magnetic nanoparticles (Pd–SMU-MNPs) as an efficient and magnetically reusable nanocatalyst was prepared and applied for the Heck and Suzuki cross-coupling reactions. All coupling reactions proceeded in short reaction times with good to excellent yields. After completion of reactions, the catalyst was easily separated from the reaction mixture using an external magnetic field and reused for several consecutive runs without significant loss of its catalytic efficiency and activity. This nanomagnetic catalyst was characterized by FT-IR spectroscopy, XRD, VSM, ICP-OES, TEM and SEM techniques. The leaching of the catalyst has been examined by a hot filtration test and ICP-OES analysis.     

电感耦合等离子体发射光谱法测定膨化食品中铝

目的探讨微波消解-电感耦合等离子体发射光谱法(ICP-OES)测定膨化食品中铝的可行性。方法样品经微波消解后,采用ICP-OES对膨化食品中铝进行测定。结果 ICP-OES法相对标准偏差(RSD)4.0%,线性相关系数0.999 9,回收率88.46%。结论 ICP-OES测定膨化食品中铝具有RSD小、线性相关系数好、准确度高、测定快速等优点,是测定膨化食品中铝的理想方法。     

不同前处理方法测定银锡焊料中3种重金属元素

选用银含量为3%、30%和70%的银锡焊料样品,分别经过三种不同前处理方法,采用硝酸、盐酸消解,应用电感耦合等离子体发射光谱法(ICP-OES)同时测定锡铅合金中镉、铅、汞3种重金属元素含量。实验研究了不同前处理方法对银锡合金中重金属测定的影响。实验表明消解实验中的共沉淀现象会对3种重金属元素的测定产生不利的影响,回收率不能满足要求;采用硝酸消解,过滤残渣经王水消解的方法,镉、铅、汞的7次测定重复性相对标准偏差在2.7%~5.5%、加标回收率在85.6%~103%,能够满足RoHS测试要求。     

Microwave-assisted aqua regia digestion for determining platinum,palladium, rhodium and lead in catalyst materials

This study investigated a microwave-assisted aqua regia digestion of catalyst samples prior to the determination of Pt, Pd, Rh and Pb by ICP-OES. While optimising the method, the effect of digestion temperature on the digestion efficiency was investigated. Few aqua regia digestions were also carried out using a high pressure asher, with a digestion temperature of 280 °C. In addition, XRD (X-ray diffractometry) was used to characterise digestion residue. The study showed that accurate and reliable results for Pt, Pd, Rh and Pb in a recycled monolith catalyst (NIST SRM 2557) were obtained by ICP-OES after the microwave assisted aqua regia digestion. The amounts of Pt, Pd and Rh in the prepared catalyst samples were also at the expected levels. Furthermore, the results indicated that the main part of the impurities and supporting material elements can be quantitatively extracted from the catalyst samples by using the microwave-assisted aqua regia sample pre-treatment.     

High-throughput screening of surface displayed gene products

With the human genome project approaching completion, there is a growing interest in functional analysis of gene products. The characterization of large numbers of proteins, their expression patterns and in vivo localisations, demands the use of automated technology that maintains a logistic link to the encoding genes. As a complementary approach, phage display is used for recombinant protein expression and the selection of interacting (binding) molecules. Cloning of libraries in filamentous bacteriophage or phage mid vectors provides a physical link between the expressed protein and its encoding DNA sequence. High-throughput technology for automated library handling and phage display selection has been developed using picking-spotting robots and a module for pin-based magnetic particle handling. This system enables simultaneous interaction screening of libraries and the selection of binders to different target molecules at high throughput. Target molecules are either displayed on high-density filter membranes (protein filters) or tag-bound to magnetic particles and can be handled as native ligands. Binding activity is confirmed by magnetic particle ELISA in the microtitre format. The whole procedure from immobilisation of target molecules to confirmed clones of binders is automatable. Using this technology, we have selected human scFv antibody fragments against expression products of human cDNA libraries.     

A simple solution to expanding available reference materials for Laser Ablation Inductively Coupled Plasma Mass Spectrometry analysis: Applications to sedimentary materials

Analytical data on sediments are of great importance in understanding and documenting environmental issues. For laboratories interested in in-situ chemical analysis of sediments by LA-ICP-MS, a major issue is the lack of appropriate matrix matched sediment reference materials. Those available were largely designed for partial extractions which generally do not reflect the total elemental compositions. In this work we provide a comprehensive study on chemical compositions of seven currently available sediment reference materials (Lake sediments: LKSD-1, LKSD-2, LKSD-3, Stream sediments: STSD-2, STSD-3, and Marine sediments: PACS-2, MESS-3) as determined by Solution Nebulization Inductively Coupled Plasma Mass Spectrometry (SN-ICP-MS) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after digestion in a mixture of concentrated HNO₃ and HF acids. We also report a simple method to prepare these sediment reference materials and more generally appropriate sediment cores for LA-ICP-MS analysis using epoxy resin. This sample preparation method maintains sediment integrity for high spatial resolution analysis which is required for tracing changes in environmental conditions over short time periods. This work also demonstrates the application of fs-LA-ICP-MS as a tool for direct, rapid and high spatial resolution analysis of sediments.     

A comparison of scanning electron microscopy energy dispersive X-ray (SEM/EDX) and inductively coupled plasma optical emission spectrometry (ICP-OES) for provenance inferences of grog-tempered Bronze Age pottery

Pottery tempered with former pottery fragments (named grogs) is very common during the Bronze Age in the Cantabrian Cornice (North Spain). Grog tempered pottery from two coeval archaeological sites Santa Maria de Estarrona and Peracho are studied in order to establishes pottery provenance. Chemical analyses of pottery are used to discriminate locally from imported pottery under the assumption that different geological regions exhibit a distinctive chemical fingerprint. However, the pottery-maker usually transforms the original clay by tempering and prepares the material suitable for firing modifying the raw material chemical fingerprint. The problem increases when grogs are used as tempering agent. In these cases the chemical input is clearly contaminated with foreign materials making impossible to assign a source area. SEM-EDX has been applied to both the matrix and the different types of grog tempers and the results have been compared to the whole potsherd analysis performed by ICP-OES. Chemometric analysis of matrices enable to discriminate different raw materials that can be attributed to locally produced pottery. This chemical characterization of the matrices by SEM-EDX is more effective than the chemical composition determined for the whole potsherd by ICP-OES. The occurrence of grogs within grog tempers and various types of grogs indicates modes of production based on intensive recycling. The presence of some pottery vessels at the Estarrona site with chemical features similar to those of Peracho is indicative of the transport of pieces during the migrations of semi-sedentary groups and/or the exchange of pieces between different groups of humans.     

Microwave-assisted sample preparation in analytical chemistry

The speed and efficiency of instrumentation for chemical analysis has improved dramatically over the past twenty years. Until recently, however, methods of sample preparation had not changed to keep pace, so this had become the slowest step in analytical chemistry methodology. The widespread adoption of domestic microwave ovens during the past twenty-five years has eventually led to their usage in chemical laboratories. Microwave technology has now advanced to the point where it is revolutionizing chemical sample preparation and chemical synthesis. Since the first application of a microwave oven for sample preparation in 1975, many microwave-assisted dissolution methods have been developed - these are applicable to virtually any kind of sample type. This review attempts to summarize all the microwave-assisted dissolution and digestion methods reported up to and including 1994. In addition, some very recent developments in continuous-flow automated dissolution systems are discussed, as is the emergence of databases and software packages related to the application of microwave technology to sample dissolution. There are 344 references.     

Selective analysis of phosphopeptides within a protein mixture by chemical modification, reversible biotinylation and mass spectrometry

A new method combining chemical modification and affinity purification is described for the characterization of serine and threonine phosphopeptides in proteins. The method is based on the conversion of phosphoserine and phosphothreonine residues to S-(2-mercaptoethyl)cysteinyl or beta-methyl-S-(2-mercaptoethyl)cysteinyl residues by beta-elimination/1,2-ethanedithiol addition, followed by reversible biotinylation of the modified proteins. After trypsin digestion, the biotinylated peptides were affinity-isolated and enriched, and subsequently subjected to structural characterization by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Database searching allowed for automated identification of modified residues that were originally phosphorylated. The applicability of the method is demonstrated by the identification of all known phosphorylation sites in a mixture of alpha-casein, beta-casein, and ovalbumin. The technique has potential for adaptations to proteome-wide analysis of protein phosphorylation.