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1.
Mass Spectrom Rev ; 37(1): 43-56, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-27155889

RESUMO

The manuscript reviews the various mass spectrometric techniques for analysis and chemical studies of Americium. These methods include thermal ionization mass spectrometry (TIMS), and inductively coupled plasma source mass spectrometry (ICPMS) for the determination of Am isotope ratios and concentration in nuclear fuel samples of interest in nuclear technology, and in complex biological and environmental samples. Ultra-sensitive mass spectrometric techniques of resonance-ionization mass spectrometry (RIMS), and accelerator-based mass spectrometry (AMS) are also discussed. The novel applications of electrospray ionization mass spectrometry (ESIMS) to understand the solution chemistry of Am and other actinides are presented. These studies are important in view of the world-wide efforts to develop novel complexing agents to separate lanthanides and minor actinides (Am, Np, and Cm) for partitioning and transmutation of minor actinides from the point of view of nuclear waste management. These mass spectrometry experiments are also of great interest to examine the covalent character of actinides with increasing atomic number. Studies on gas-phase chemistry of Am and its oxides with Knudsen effusion mass spectrometry (KEMS), Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS), and laser-based experiments with reflectron time-of-flight mass spectrometer (R-ToF) are highlighted. These studies are important to understand the fundamental chemistry of 5f electrons in actinides. Requirement of certified isotopic reference materials of Am to improve the accuracy of experimental nuclear data (e.g., the half-life of 243 Am) is emphasized. © 2016 Wiley Periodicals, Inc. Mass Spec Rev.

2.
Mass Spectrom Rev ; 36(4): 499-519, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-26757103

RESUMO

The present review discusses different mass spectrometric techniques-viz, thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS), and secondary ion mass spectrometry (SIMS)-used to determine 11 B/10 B isotope ratio, and concentration of boron required for various applications in earth sciences, marine geochemistry, nuclear technology, environmental, and agriculture sciences, etc. The details of the techniques-P-TIMS, which uses Cs2 BO2+ , N-TIMS, which uses BO2- , and MC-ICPMS, which uses B+ ions for bulk analysis or B- and B+ ions for in situ micro-analysis with SIMS-are highlighted. The capabilities, advantages, limitations, and problems in each mass spectrometric technique are summarized. The results of international interlaboratory comparison experiments conducted at different times are summarized. The certified isotopic reference materials available for boron are also listed. Recent developments in laser ablation (LA) ICPMS and QQQ-ICPMS for solids analysis and MS/MS analysis, respectively, are included. The different aspects of sample preparation and analytical chemistry of boron are summarized. Finally, the future requirements of boron isotope ratios for future applications are also given. Presently, MC-ICPMS provides the best precision and accuracy (0.2-0.4‰) on isotope ratio measurements, whereas N-TIMS holds the potential to analyze smallest amount of boron, but has the issue of bias (+2‰ to 4‰) which needs further investigations. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:499-519, 2017.

3.
Environ Geochem Health ; 38(3): 737-48, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26254888

RESUMO

Isotopic compositions of B and Sr in rocks and sediments can be used as tracers for plant provincial sources. This study aims to test whether tea leaf origin can be discriminated using (10)B/(11)B and Sr isotopic composition data, along with concentrations of major/trace elements, in tea specimens collected from major plantation gardens in Taiwan. The tea leaves were digested by microwave and analyzed by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The data showed significant variations in (87)Sr/(86)Sr ratios (from 0.70482 to 0.71462), which reflect changes in soil, groundwater or irrigation conditions. The most radiogenic tea leaves were found at the Taitung garden and the least radiogenic ones were from the Hualien garden. The δ (11)B was found to change appreciably (δ (11)B = 0.38-23.73 ‰) which could be due to fertilizers. The maximum δ (11)B was also observed in tea samples from the Hualien garden. Principal component analysis combining (87)Sr/(86)Sr, δ (11)B and major/trace elements results successfully discriminated different sources of major tea gardens in Taiwan, except the Hualien gardens, and this may be due to rather complicated local geological settings.


Assuntos
Boro/análise , Camellia sinensis/química , Isótopos de Estrôncio/análise , Oligoelementos/análise , Isótopos/análise , Espectrometria de Massas , Folhas de Planta/química , Taiwan , Chá/química
4.
Anal Methods ; 3(2): 322-327, 2011 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32938031

RESUMO

Studies were carried out to determine the 10B/11B isotope ratio by positive thermal ionization mass spectrometry (P-TIMS) analyzing boron as rubidium borate ions. Of the 36 different ionic species formed, the boron and rubidium isotope ratios were obtained from the ion intensity ratios of the most suitable ion pairs corresponding to masses 212, 213 and 215, 213 respectively. The investigations were carried out to explore the possibility of correcting the observed isotope ratio of boron by using a modified internal normalization technique based on the observed Rb isotope ratio. The method is based on the relation of isotopic fractionation of boron as a function of the rubidium (natural isotopic composition) isotopes fractionation obtained during TIMS analysis from the same filament loading. The application of the methodology to improve the precision of the observed 10B/11B isotope ratio during analysis of irradiated boron alloy samples is demonstrated. Improvement in precision from 0.25% to better than 0.05% was demonstrated using this approach.

5.
Talanta ; 82(4): 1378-84, 2010 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-20801344

RESUMO

An improved technique for precise and accurate determination of boron isotopic composition in Na-rich natural waters (groundwater, seawater) and marine biogenic carbonates was developed. This study used a 'micro-sublimation' technique to separate B from natural sample matrices in place of the conventional ion-exchange extraction. By adjusting analyte to appropriate pH, quantitative recovery of boron can be achieved (>98%) and the B procedural blank is limited to <8 pg. An additional mass bias effect in MC-ICP-MS was observed which could not be improved via the standard-sample-standard bracketing or the 'pseudo internal' normalization by Li. Therefore a standard other than NBS SRM 951 was used to monitor plasma condition in order to maintain analytical accuracy. An isotope cross-calibration with results from TIMS shows that the space-charge mass bias on MC-ICP-MS can be successfully corrected using off-line mathematical manipulation. Several reference materials, including the seawater IAPSO and two groundwater standards IAEA-B-2 and IAEA-B-3, were used to validate this approach. We found that the delta(11)B of the reference coral JCp-1 was 24.22+/-0.28 per thousand, corresponding to seawater pH based on the coral delta(11)B-pH function.

6.
Appl Opt ; 47(31): G58-64, 2008 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-19122703

RESUMO

Laser-induced breakdown spectrometry (LIBS) has been successfully developed to quantify thorium (Th) and uranium (U) in solution using membrane-based filter paper as a sample support. The filter paper is easy to handle and the entire analysis process takes only a few minutes for each sample. The developed method provides a practical approach for fast and sensitive determination of actinides in aqueous solutions using LIBS. We obtained calibration curves for U and Th individually as well as as a mixture. We observed that the quantification of trace levels of U in a bulk amount of Th was not possible because of strong spectral interference from Th at the most intense lines of U, but traces of Th in a bulk amount of U could be determined. The concentrations of U and Th in unknown solutions were determined by use of LIBS, and these results agreed to within 4% and 2%, respectively, with the expected values. The limits of detection for Th and U were calculated from the experimental data and were in the range of a few parts per million by weight to a few tens of parts per million by weight.

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