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JA0042 Electrospray ionisation mass spectrometric studies for the determination of palladium after pre-concentration by disposable pipette extraction
来源:Rapid Commun. Mass Spectrom. | 作者:P. G. Jaison | 发布时间: 2066天前 | 3943 次浏览 | 分享到:
RATIONALE: Electrospray ionisation mass spectrometric (ESI-MS) analysis of Pd in complex matrices is difficult due to the multiplicity of matrix effects. Two different approaches, internal standard and matrix separation, were investigated for developing a reliable analytical procedure for the trace level determination of Pd in simulated high-level liquid waste (SHLLW) solutions. METHODS: An ESI mass spectrometer with a quadrupole-time-of-flight analyser was used to study the speciation of the palladium-benzoylthiourea (Pd-BTU) complex and to determine the Pd content. The Pd-BTU complex was selectively pre-concentrated using disposable pipette extraction (DPX). Extraction parameters as well as ESI-MS parameters such as concentration of BTU, acidity, composition of medium and capillary voltage, etc., were optimized based on the major species [Pd(BTU)2S]+. RESULTS: The method gave quantitative and selective pre-concentration of the Pd-BTU complex from SHLLW. Linearity from 5 ppb to 200 ppb and a limit of detection of 0.012 ppb were obtained for Pd. No interference from the neighboring elements, viz. ruthenium, rhodium, silver and cadmium, was observed during the determination of Pd based on the [Pd(BTU)2S]+ peak. The ESI signal intensity was not influenced by the presence of the many other elements in the SHLLW solution. CONCLUSIONS: Good sensitivity, tolerance to matrix concentration and the absence of interference from neighboring elements make the method very promising for the determination of Pd at low levels in complex samples. We have demonstrated the capability of ESI-MS for the quantification of Pd in complex matrices and its potential for providing data on speciation, using the Pd-BTU complex. Copyright © 2012 John Wiley & Sons, Ltd.
1 Introduction

Platinum group elements (PGEs) find extensive use in high technology applications due to their unique chemical and physical properties. Some of these are in vehicle exhaust catalysts, medicine, electronic and chemical industries, etc. The widespread use of PGEs for various applications, particularly in vehicle catalytic converters and tumor treatment, etc., is leading to the increased release of these elements into the environment. Studies have shown that, under suitable conditions, certain chemical forms of PGEs emitted from vehicles could become bioavailable.[1,2] Determination of these elements is important for understanding the chemical nature of PGEs in environmental samples and their impact on ecological and biological systems.[35] The metallic forms of PGEs are generally considered to be inert as regards biological reactions. On the other hand, certain PGE compounds are known to be cytotoxic and to have mutagenic and carcinogenic effects and they are among the most potent allergens and sensitizers.[3] Due to the increase in the use of Pd in place of Pt in catalytic convertors, a predominance of the former element in airborne particulate matter has been observed over the last decade.[6] This increase in the concentrations of Pd in environmental samples is of concern because, among the PGEs, Pd has the highest bio-accessibility and mobility in the environment.[7] The process of thermal neutron induced fission of fissile nuclides, e.g. 235U, 239Pu, leads to the production of a wide range of fission products in varying quantities. Palladium (Pd), rhodium (Rh) and ruthenium (Ru) are the only three PGEs formed to a significant extent during the nuclear fission process. The actual amounts of formation of these PGEs depend on the type of reactor system as well as on the burn-up of the nuclear fuel.[8,9] With the future development of a proper recovery and decontamination process, the availability of these metals is likely to increase and they can thus serve as an alternative resource to meet the increasing demand for noble metals.[10] A reliable analytical procedure for the quantification of the PGEs is, therefore, important at different stages of reprocessing. Analytical methods have been described for the determination of PGEs in synthetic and actual nuclear waste solutions.[11,12]


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