Determination of Ultra-Trace Amouris of Uranium by Icp-Aes Technique

Abstract

An Atomic Emission Spectrometric method based on the use of Inductively coupled argon Plasma source has been developed for the determination of ultra trace concentrations of uranium in aqueous solutions. Using the optimised experimental conditions for the ICP source, uranium can be determined at 0.05 μg/ml concentration in 0.3M HNO₃ solutions with either of the two analytical lines viz. 3859.6 Å or 4090.1 Å. The precision of determinations at the lowest detection limit is better than 2% R.S.D. The uranium estimation has been corrected for the interference due to the presence of eighteen metallic elements using an inter-element correction procedure. A number of spiked samples and NBL reference samples with concomitant impurities have been analysed using the standardised procedure and good agreement has been observed with their certified values.     

萃取色谱分离-原子发射光谱测定超高纯氧化铥、氧化镱和氧化镥中痕量稀土杂质

用２－乙基己基膦酸单２－乙基己酯萃取色谱分离－原子发射光谱测定超高纯Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３中痕量稀土杂质，可用于纯度为９９．９９９９％～９９．９９９９９％（不含非稀土杂质）Ｔｍ２Ｏ３、Ｙｂ２Ｏ３、Ｌｕ２Ｏ３的纯度分析，１４个稀土杂质的回收率在６７％～１３３％之间；相对标准偏差 ５．１％～２３．２％；分离周期 １０～１３ ｈ。     

Quality assessment for tramadol in pharmaceutical preparations with thin layer chromatography and densitometry

Research studies have been carried out to develop a chromatographic and densitometric method suitable for identification and determination of tramadol and impurities. In addition, the stability of tramadol in solutions was investigated, including an effect of solution pH, temperature and incubation time. In the first instance the conditions for identification and quantitative determination of tramadol and impurities in pharmaceutical preparations were established. The separation was performed on silica gel-coated chromatographic plates (HPTLC) using two mobile phases: (I) chloroform-methanol-glacial acetic acid (9:2:0.1, v/v/v); (II) chloroform-toluene-ethanol (9:8:1, v/v/v). The UV densitometry was carried out at lambda = 270 nm. The developed method is of high sensitivity and low detection and determination limits ranging from 0.044 to 0.35 microg. For individual constituents the recovery ranges from 93.23 to 99.66%. The next step was to evaluate the stability of tramadol and determine a method of decomposition under various experimental conditions. It was found that tramadol decomposes in various ways in acidic and basic environments producing (1RS)-[2-(3-methoxyphenyl)cyclohex-2-enyl]-N,N-dimethylmethanamine (imp. B) and (1RS, 2RS)-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol (imp. cis-T) or imp. cis-T, respectively.     

Spectral-isotopic method of determination of gas-forming elements in organic and inorganic substances

A review is given of the latest papers on the application of the spectral-isotopic method of determination of gas-forming impurities in organic and inorganic materials. Main attention is paid to a new kind of investigation, i.e. the development of spectroscopic methods for isotopic analyses of nitrogen, carbon, oxygen, and hydrogen in biological objects for use in analytical monitoring in biological experiments with “tracers”. A universal method is described for the preparation of natural samples, for the separation of the gases to be analyzed from the sample, and for their purification from the impurities. The main characteristics are given of the methods for individual determination of the above elements and for joint analyses of some elements (N¹⁵-C¹³-H²) in one analytical cycle (spectrum excitation conditions, isotope concentration calculations, etc.). The characteristics of the methods have been compared with the results of other researches and the scope of our method for applications in biological investigations with tracers has been defined. The main results of spectral-isotopic method development in the traditional direction, i.e. for quantitative analysis of impurities in solid inorganic materials and for gas analysis, are produced.     

Direct determination of bioavailable molybdenum in carbon nanotubes

Bioavailable residual metallic impurities within carbon nanotubes (CNTs) are responsible for the toxicity of CNTs. Herein we present a method for fast, sensitive determination of bioavailable molybdenum residual catalyst impurities within CNTs by using electrochemical oxidation in neutral pH buffers at low potentials. This method is unique because no other method can rapidly distinguish between bioavailable/mobilizable impurities from defects in CNTs and between the total amounts of impurities. This method will be indispensable for future toxicological studies of CNTs.     

Determination of metallic impurities in a silicon wafer by local etching and electrothermal atomic absorption spectrometry.

An etching technique for the determination of the metallic impurities distribution in silicon wafers has been developed. An area of 10 mmphi and 10 microm depth was etched by 100 microL of an etching solution with a HF and HNO3 mixture. The acid matrix was evaporated on the wafer surface by IR lamp illumination and vacuum exhaust. Metallic impurities remaining on the wafer surface were redissolved into the collection solution, which was measured by electrothermal atomic absorption spectrometry (ET-AAS). The recovery invested by local etching/ET-AAS was within 95 - 112% for Fe, Cu and Ni. The detection limit (3sigma) for Fe, Cu and Ni in silicon was 1 x 10(13) atoms/cm3. To confirm the applicability, local etching was applied to evaluate the effects of metallic impurities in a gettering study and the electronic properties of semiconductor devices. It was found that local etching is a useful sample preparation technique for the analysis of metallic impurities in a specific area on a silicon wafer.     

邻苯二甲酸二(2-乙基)己酯和偏苯三酸三辛酯在临床不同药液中溶出量的比较

聚氯乙烯(PVC)材质的医疗器械产品中需要加入增塑剂以改善柔韧性,目前最常用的增塑剂是邻苯二甲酸二(2-乙基)己酯(DEHP)和偏苯三酸三辛酯(TOTM)。本文考察了PVC一次性使用输液器产品在脂溶性药液(紫杉醇注射液)、肠外营养液(脂肪乳)、酸性药液(左氧氟沙星,pH 3.0~5.0)和碱性药液(呋塞米,pH 8.0~9.0)中的DEHP和TOTM溶出量,并进行对比分析。先建立了一种高效液相色谱-紫外检测(HPLC-UV)方法测定增塑剂的溶出量,并利用该方法对增塑剂的溶出量进行了分析。实验结果表明,增塑剂在不同药液中均有一定的溶出情况,其中紫杉醇注射液对增塑剂的溶出量要高于脂肪乳,并远高于左氧氟沙星和呋塞米注射液。通过对比DEHP和TOTM的溶出量可以看出,在相同的浸提条件下,TOTM的溶出量远低于DEHP的溶出量。利用紫杉醇注射液浸提24 h,PVC输液器产品DEHP的溶出量为21.14 mg,而TOTM的溶出量仅为0.078 mg。DEHP的溶出量为TOTM溶出量的270倍。因此,TOTM具有的较好耐迁移性,是一种潜在的DEHP替代增塑剂。     

ICP-OES法快速检测药品中催化剂残留的14种重金属元素

采用有机溶剂二甲基亚砜和水(4∶1)的混合溶剂溶解药物样品,建立了电感耦合等离子体发射光谱法(ICP-OES)直接检测药物产品中金属催化剂残留的方法。在优化实验条件下,该法能快速检测欧洲药物评审委员会(EMEA)颁布指南中的14种重金属元素;方法检出限均小于0.30 mg/kg,加标回收率在90%～115%之间;对不同前处理方法的数据结果进行了对比。实验结果表明,该法操作简单、快速、准确度高,适合大批量药物产品中多元素的快速检测。     

Bestimmung und abtrennung von sauerstoffverunreinigungen in reinst-selenThe determination and separation of oxygen impurities in high-purity selenium

(The determination and separation of oxygen impurities in high-purity selenium)By distillation in high vacuum, high-purity selenium is almost completely freed from impurities caused by metallic elements, oxides and water. If bulk vitreous selenium has a suitable thermal history, the oxygen content may be determined from the intensity of the oxide absorption band at 932 cm^?1 in the i.r. spectrum of the glass. In distilled selenium this content is < 1 × 10^?4 wt.< %.     

Selective ion exchange separation of uranium from concomitant impurities in uranium materials and subsequent determination of the impurities by ICP-OES

An ion exchange method has been developed for the separation of uranium from trace level metallic impurities prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES) in uranium materials. Selective separation of uranium from trace level metallic impurities consisting Cr, Co, Cu, Fe, Mn, Cd, Gd, Dy, Ni, and Ca was achieved on anion exchange resin Dowex 1 × 8 in sulphate medium. The resin (100–200 mesh, in chloride form) was packed in a small Teflon column (7.8 cm × 0.8 cm I.D.) and brought into sulphate form by passing 0.2 N ammonium sulphate solution. Optimum experimental conditions including pH and concentration of sulphate in the liquid phase were investigated for the effective uptake of uranium by the column. Uranium was selectively retained on the column as anionic complex with sulphate, while impurities were passed through the column. Post column solution was collected and analyzed by ICP-OES for the determination of metallic impurities. Up to 2,500 μg/mL of uranium was retained with >99% efficiency after passing 25 mL sample through the column at pH 3. Percentage recoveries obtained for most of the metallic impurities were >95% with relative standard deviations <5%. The method established was applied for the determination of gadolinium in urania–gadolinia (UO₂–Gd₂O₃) ceramic nuclear fuel and excellent results were achieved. Solvent extraction method using tributylphosphate (TBP) as extractant was also applied for the separation of uranium in urania–gadolinia nuclear fuel samples prior to the determination of gadolinium by ICP-OES. The results obtained with the present method were found very comparable with those of the solvent extraction method.     

Reversed-phase column extractive separation of germanium with bis(2-ethylhexyl)phosphoric acid

Germanium was quantitatively extracted from 6–10 M hydrochloric acid on a silica gel column coated with bis(2-ethylhexyl)phosphoric acid and stripped with various acids. Germanium was then determined spectrophotometrically as its complex with phenylfluorone. Germanium was effectively separated from large numbers of main group and transition elements. The determination of germanium in fly ash by the proposed method is reported.     

Ultra-clean Si(111) and Si(001) Surfaces Prepared by Advanced Wet Chemical Cleaning

Wet chemical cleaning of silicon is a critical step, e.g., pre-gate clean, in the semiconductor manufacturing^[1]. For example, pre-gate oxide cleaning demands ultra-clean silicon surface with least surface roughness. It is well known that metallic infinities and roughness cause the lower breakdown voltage in gate dielectric^[2]. It has stringent requirements for ultra-clean and atomically flat silicon surface as the thickness of gate oxide is decreasing. In the present work, we have extended our study on Si(100) surface13] and extensively investigated wet chemical cleaning of Si(111) and Si(100) surfaces in NH₄F-based solutions by using scanning tunneling microscopy (STM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and total reflection X-ray fluorescence spectrometry (TXRF). Surface roughness, organic contamination, metallic impurities and surface termination on the silicon surfaces after wet chemical cleaning with various NH₄F-based solutions have been determined and compared with those treated with RCA cleans, HF solutions and other industrially used solutions. Our results indicate that ultra-clean and smooth Si(111) and Si(001) surfaces are obtained by treatment with NH4F-based solutions.     

Studies on the extraction behavior of Zr(IV), Ce(III), Th(IV) and U(VI) from aqueous solutions of Arsenazo-I with HDEHP,HTTA, TDA and TCMA

The extraction behavior of Zr(IV), Ce(III), Th(IV) and U(VI) from aqueous solutions containing Arsenazo-I with the organic solvents tridodecylamine (TDA), 1-[thenoyl-(2)]-3-3-3-trifluoroacetone (HTTA), di(2-ethylhexyl) phosphoric acid (HDEHP) and tricaprylmethylammonium chloride (TCMA) in xylene has been investigated. Effect of hydrogen ion concentration in the aqueous phase, Arsenazo-I concentration, as well as the effect of solvent concentration on the extraction was studied. Some alternatives for separation of the elements studied were recommended enabling the spectrophotometric determination of these elements using Arsenazo-I without interference.     

Determination of Traces of Copper,Lead, and Cadmium in Cobalt by Derivative Pulse Polarography

Abstract

A derivative pulse polarographic method is described for determining traces of copper, lead and cadmium in cobalt and its compounds without separation. In hydrochloric acid medium the detection limits are respectively about 0.02, 0.04 and 0.1 ppm in metallic cobalt when analysing 2 M cobalt solutions. The procedure was applied to the analyses of synthetic and commercially available cobalt samples and showed a satisfactory sensitivity and precision at various concentrations levels of the three impurities.     

Spectrophotometric study of the solubility and the protolytic properties of 1-(2-pyridylazo)-2-naphthol in different ethanol–water solutions

The solubility and the protolytic constants of 1-(2-pyridylazo)-2-naphthol (PAN) have been accurately determined at temperatures between 20.0 and 30.0°C in ethanol–water solutions with ethanol concentrations ranging from 10.0% to 95.0% (v/v). The measurement of the protolytic constants is based on the spectrophotometric determination of the concentrations of the corresponding conjugate acid–base pairs in ethanol–water solutions containing PAN and hydrochloric acid or sodium hydroxide. The traditionally used pH measurements in such studies in non-aqueous solutions are thus avoided. The solubility and the protolytic constants of PAN in pure water have been calculated by extrapolating the ethanol–water results to pure water where PAN is practically insoluble. The determination of the thermodynamic data mentioned above is necessary for elucidating the interactions of PAN with various metal ions in solutions and in cation-exchange membranes (e.g., Nafion^®) used as PAN-based optodes.     

Trace analysis of lithium metal by PIXE

A rapid method is described for simultaneous trace determination of metallic impurities in lithium metal by Particle Induced X-ray Emission (PIXE) technique. The impurities were preconcentrated by ion-exchange separation using a weak cation exchanger, Bio Rex-70 and analyzed by 2.34 MeV protons. The reliability of the method was tested by analyzing synthetic samples having several metallic impurities at 1–5 ppm range.     

Analytical application of DHOA for the determination of trace metallic constituents in U based fuel materials by ICP-AES

DHOA (Di-n-hexyl-octanamide) is one of the alternative extractants to TBP (tri-n-butyl phosphate) known for the extraction of uranium from moderate nitric acid medium without significant extraction of the fission products. Analytical application of DHOA was explored to develop a methodology for determination of trace metallic constituents in uranium based nuclear materials. This involved the separation of uranium matrix by 1.1 M DHOA-dodecane followed by the analysis of the raffinate for trace constituents by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). A systematic study showed that four contacts of 1.1 M DHOA-dodecane were required for quantitative extraction of U from 4 M HNO₃ feed for the sample size of 1 g in 10 mL. The feasibility of using DHOA for extraction of U from trace metallic constituents in U based fuel materials without losing trace quantities of analytes of interest was studied by using synthetic samples after appropriate spiking of common impurities and critical elements at their required specification limits (common elements—5 ppm, critical elements—1 ppm). A systematic study was carried out to compare the analytical performance of DHOA with TBP, which revealed that DHOA could successfully be employed for the determination of 19 trace constituents with lower estimation limits of 5 ppm for common impurities and 1 ppm for critical elements.     

离子色谱-膜去溶-ICP-MS法测定高纯钨粉中痕量金属杂质

灵敏地检测了高纯钨粉中的痕量金属杂质.钨粉用H2O2溶解后进入离子色谱的阳离子交换柱,经水淋洗后,用HNO3洗脱,洗脱后的溶液经过膜去溶装置雾化去溶后进入电感耦合等离子体质谱检测.除B,V,Sb外,其它杂质元素如Mg,Al,Ti,Cr,Be,Fe,Mn,Co,Ni,Cu,Zn,Ga,Sr,Cd,Ba等的回收率均在90%～107%之间,检出限在0.001～0.5μg/g之间.     

Determination of rare-earth elements by high-performance liquid chromatography/inductively-coupled plasma/atomic emission spectrometry

Liquid chromatography coupled on-line to a sequential ICP/AES system is applied for the determination of 14 rare-earth elements (REEs) in samples with widely different concentrations of REEs and matrix elements. The REEs are separated on a cation-exchanger by applying an α- hydroxyisobutyric acid gradient. The determination limits were the same as those obtained by continuous nebulization of single-element standard solutions. The chromatographic separation precludes mutual spectral interferences between the REEs. The practical value of the method developed is demonstrated by the determination of REE impurities in Specpure rare-earth oxides, by its demonstrated potential to evaluate real spectral interferences, and by the analysis of geological samples (natural phosphates) with relatively low total REE contents. The detection limits of REEs in these natural phosphates ranged between 0.005 and 0.4 μg g^?1.     

Application of cobalt ammine complexes for the simultaneous determination of traces of As,Fe, Ti,V and Zr in high-purity cobalt metal by lanthanum hydroxide coprecipitation and inductively coupled plasma-atomic emission spectrometry

Co is not coprecipitated with lanthanum hydroxide in ammonium hydroxide solution due to the formation of soluble salts of cobalt ammine complexes. This complexation reaction has been applied to the simultaneous determination of five trace impurities (As, Fe, Ti, V and Zr) in high-purity Co metal by inductively coupled plasma-atomic emission spectrometry. Warming the solution and double coprecipitation are effective for separating the trace elements simultaneously from a large amount of cobalt ammine complexes. Matrix-matched solutions are used for calibration. The detection limits of the five elements are in the range of 0.06 and 0.6 microg/g and the recoveries are quantitative.