Available options for the determination of ultra trace elements in pristine environments (original) (raw)
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Analytical and Bioanalytical Chemistry, 2004
A procedure is described for the determination of Y, Zr, Nb, Ru, Rh, Pd, Ag, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Bi, and U in human urine and serum at concentrations relevant to the occupationally unexposed population. Sample preparation was limited to tenfold dilution with 2% HCl. A combination of a sample-introduction system designed to provide enhanced sensitivity and the use of water and acids of high-purity has resulted in limits of quantification (LOQ) in the sub-nanogram per liter range for 13 analytes. Instrumental background caused by release of analytes (Y, Zr, Ag, Sb, Au, Tl, Bi, U) from different parts of the sample-introduction system was found to be the major limitation in obtaining even better LOQ. Nevertheless, detection capabilities of the proposed procedure were adequate for all elements except Ru, Pd, and Rh. Despite of the use of high-resolution mode for these analytes some unresolved spectral interferences might still be present. For 13 elements an external accuracy assessment was accomplished by participation in proficiency testing and inter-comparison programs. Results obtained for pooled urine and serum were compared with concentrations reported for occupationally unexposed populations in recent publications.
Sources of contamination and remedial strategies in the multi-elemental trace analysis laboratory
Analytical and Bioanalytical Chemistry, 2010
In theory, state of the art inductively coupled plasma mass spectrometry (ICP-MS) instrumentation has the prerequisite sensitivity to carry out multi-elemental trace analyses at sub-ng L −1 to sub-pg L −1 levels in solution. In practice, constraints mainly imposed by various sources of contamination in the laboratory and the instrument itself, and the need to dilute sample solutions prior to analysis ultimately limit detection capabilities. Here we review these sources of contamination and, wherever possible, propose remedial strategies that we have found efficacious for ameliorating their impact on the results of multi-elemental trace analyses by ICP-MS. We conclude by providing a list of key points to consider when developing methods and preparing the laboratory to routinely meet the demands of multi-elemental analyses at trace analytical levels by ICP-MS.
Fresenius Journal of Analytical Chemistry, 1999
During the past decade, inductively coupled plasma mass spectrometry (ICPMS) has evolved from a delicate research tool, intended for the well-trained scientist only, into a more robust and well-established analytical technique for trace and ultra-trace element determination, with a few thousand of instruments used worldwide. Despite this immense success, it should be realized that in its 'standard configuration' -i.e. equipped with a pneumatic nebulizer for sample introduction and with a quadrupole filter -ICPMS also shows a number of important limitations and disadvantages: (i) the occurrence of spectral interferences may hamper accurate trace element determination, (ii) solid samples have to be taken into solution prior to analysis and (iii) no information on the 'chemical form' in which an element appears can be obtained. Self-evidently, efforts have been and still are made to overcome the aforementioned limitations to the largest possible extent. The application of a double focusing sector field mass spectrometer in ICPMS instrumentation offers a higher mass resolution, such that spectral overlap can be avoided to an important extent. Additionally, in a sector field instrument, photons are efficiently eliminated from the ion beam, resulting in very low background intensities, making it also very well-suited for extreme trace analysis. Also the combination of the ICP as an ion source and a quadrupole filter operated in a socalled 'alternate' stability region, an ion trap or a Fourier transform ion cyclotron resonance mass spectrometer allows high(er) mass resolution to be obtained. With modern quadrupole-based instruments, important types of spectral interferences can be avoided by working under 'cool plasma' conditions or by applying a collision cell. The use of electrothermal vaporization (ETV) or especially laser ablation (LA) for sample introduction permits direct analysis of solid samples with sufficient accuracy
Applications of Inductively Coupled Plasma Mass Spectrometry to Trace Element Research and Control
The determination of chemical elements in food: …, 2007
Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) have been applied as the most important inorganic mass spectrometric techniques having multielemental capability for the characterization of solid samples in materials science. ICP-MS is used for the sensitive determination of trace and ultratrace elements in digested solutions of solid samples or of process chemicals (ultrapure water, acids and organic solutions) for the semiconductor industry with detection limits down to sub-picogram per liter levels. Whereas ICP-MS on solid samples (e.g. high-purity ceramics) sometimes requires time-consuming sample preparation for its application in materials science, and the risk of contamination is a serious drawback, a fast, direct determination of trace elements in solid materials without any sample preparation by LA-ICP-MS is possible. The detection limits for the direct analysis of solid samples by LA-ICP-MS have been determined for many elements down to the nanogram per gram range. A deterioration of detection limits was observed for elements where interferences with polyatomic ions occur. The inherent interference problem can often be solved by applying a double-focusing sector field mass spectrometer at higher mass resolution or by collision-induced reactions of polyatomic ions with a collision gas using an ICP-MS fitted with collision cell. The main problem of LA-ICP-MS is quantification if no suitable standard reference materials with a similar matrix composition are available. The calibration problem in LA-ICP-MS can be solved using on-line solution-based calibration, and different procedures, such as external calibration and standard addition, have been discussed with respect to their application in materials science. The application of isotope dilution in solution-based calibration for trace metal determination in small amounts of noble metals has been developed as a new calibration strategy. This review discusses new analytical developments and possible applications of ICP-MS and LA-ICP-MS for the quantitative determination of trace elements and in surface analysis for materials science. ᮊ
Microchemical Journal, 2014
This article describes the application of on-line isotope dilution mass spectrometry with inductively coupled plasma (OID-ICP-MS) to the field of trace metal analysis (B, Cd, Cr, Fe, Ni, Pb and Zn) in water samples by the certified reference material (CRM) characterization. Drinking, natural and waste water certified reference materials were analyzed. Emphasis is placed on OID-ICP-MS measurements of highest analytical quality and their validation against direct external calibration mass spectrometry with inductively coupled plasma analysis (ICP-MS). Differences in the calibration strategies such as single OID-ICP-MS versus direct external calibration ICP-MS were discussed. In general, it can be stated that OID-ICP-MS offers high accurate and precise results with small measurement uncertainties, when properly applied, compared to external calibration. Thus, OID-ICP-MS proved to be an ideal solution for routine water sample analysis, increasing sample throughput without any previous sample handling and improving the quality and reliability of the analytical results.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2005
The use of a new HF-resistant tandem spray chamber arrangement consisting of a cyclonic spray chamber and a Scott-type spray chamber made from PFA and PEEK provides a straightforward approach for improving the performance of inductively coupled-mass spectrometry (ICP-MS). The characteristics of the tandem spray chamber were critically evaluated against a PEEK cyclonic and a PFA Scott-type spray chamber, respectively. Sensitivity across the entire mass range was increased by about three times compared to the conventional setup utilizing only one spray chamber. Precision of the results, especially at low signal intensities, improved by 160% and 31% compared to the cyclonic and Scott-type spray chamber, respectively. Using the tandem spray chamber, the oxide formation rate was lowered by about 50%. Signals as low as 30 counts could be determined under routine measurement conditions with a RSD of 2.4% thus allowing to precisely quantify small concentration differences at the ng l À 1 concentration level. The excellent precision (0.02 -0.07%) of 206 Pb / 207 Pb and 206 Pb / 208 Pb ratios determined in pore water samples was rather limited by the instrumental capabilities of the single collector ICP-MS instrument than by the performance of the tandem spray chamber. D
Spectrochimica Acta Part B-atomic Spectroscopy, 2009
Flame-in-gas shield miniature hydride atomizers (FIGS) have been investigated and evaluated in view of their alternative use to miniature diffusion flame hydride atomizer (MDF) to determination of hydride forming elements by atomic fluorescence spectrometry (AFS). Chemical vapour generation (CVG) by aqueous phase derivatization by NaBH 4 in a continuous flow generator (CF) was employed for the generation of volatile hydrides of As, Sb, Bi, Se, Te and Sn. A dispersive AFS apparatus using electrodeless discharge lamps (EDL) as the excitation sources has been employed for both spectra acquisition and analytical determinations. The characteristics of FIGS in terms of background emission spectra, most intense AF spectral lines and limits of detection were compared with those of most popular MDF. FIGS presents a lower background emission with respect to MDF, allowing also the control of the molecular fluorescence of OH radicals in the determination of bismuth. Limits of detection for FIGS compare very well with to those obtained by MDF giving improvement factor of 5.5, 4.4, 3.6, 3.6, 0.7 an 0.5 for Bi, As, Se, Son, Te and Sb. Accuracy of FIGS has proven by determination of arsenic and antimony in seawater (NASS-5) and river water (SRLS-4) certified reference materials and bismuth in unalloyed copper (CuV 398, CuVI 399) standard reference materials by dispersive CVG-AFS.
A new spark source mass spectrometric technique for the analysis of sub-ng amounts of trace elements
Fresenius Zeitschrift f�r Analytische Chemie, 1988
Neues funkenmassenspektrometrisches Verfahren fiir die Analyse yon sub-ng-Mengen von Spurenelementen Summary. Spark source mass spectrometric "tip-top-technique" (TTT) is a new method for the analysis of sub-ng amounts of chemically separated trace elements in geological material. Besides its application to dissolved samples, TTT differs from conventional spark source mass spectrometry in reduction of measuring time (few minutes), photoplate background, and interferences by isobars and cluster-ions, resulting in enhanced sensitivities. Detection limits range from about 5 to 20 pg for the rare earth elements, U and Th, and from about 10 to 100 pg for noble metals. Precisions and accuracies of I to 5% are gained for trace elements abundances > about I ng. A potential and especially useful application of TTT is the analysis of rocks available only in very small sample sizes and/or with very low concentration levels of trace elements. An additional application is the determination of osmium isotopes in geological material.
Quantitative Analyses of Trace Elements in Environmental Samples: Options and (Im)possibilities
The main aim of contemporary ecotoxicological studies is to determine the bioavailability, toxicity and risk relationships of trace-element contaminants in ecosystems. Discussions thus focus primarily on the concentrations of elements in soils, their dynamics, and the impact they have on microorganisms, plants, animals and the ecosystem as a whole. However, before the basic ecotoxicological principles can be discussed, the appropriate analytical methods for addressing particular question(s) need to be chosen from among the broad array of physicochemical analytical methods that are available. Together with the sampling strategy and preparation, these are key issues that affect the final outcome. In this chapter, we mainly focus on the presentation and use of X-ray fluorescence/absorption-based techniques. These include standard and total reflection X-ray fluorescence, micro-proton-induced X-ray emission, and X-ray absorption spectroscopy (such as extended X-ray absorption fine structure and X-ray absorption near-edge structure) for the analysis of trace-element concentrations and their coordination in biological samples.
Spectrochimica Acta Part B: Atomic Spectroscopy, 1998
The analytical performance of a high transmission interface (S mode), inductively coupled plasma-quadrupole mass spectrometer (the VGE Plasma Quad 3) was evaluated for multitrace element analysis of geological and environmental materials. The sensitivity, limits of detection (LODs), effect of Ca and Na and other major elements on mass response, background, percentage 156 CeO + / 140 Ce + , 70 Ce ++ / 140 Ce + , and long-and short-term variations were compared with those obtained with the conventional mode (normal mode). Normal mode sensitivities varied from 20 MCPS ppm −1 (millions of counts per second per ppm) for 9 Be + , 70-80 MCPS ppm −1 for 59 Co + , 90 for 115 In + and 40-50 MCPS ppm −1 for the heavy masses. S mode sensitivities were 180 MCPS ppm −1 for 59 Co + , 350-380 for 115 In + and 140 Ce + , 300 MCPS ppm −1 for 208 Pb + , and 150 MCPS ppm −1 for 232 Th + and 238 U + , i.e. enhancements amounting to 7. Three j normal and S mode LODs are mainly in the 1-2 and 0.1 ppt range, respectively. S mode LODs are enhanced relative to the normal mode, for masses Ͼ80 amu, by factors ranging from about 10 to 50. S mode LODs are depressed relative to normal mode LODs for masses Ͻ50 amu by a factor of 10, and the extent of depression is related linearly to mass. In the high-and mid-mass ranges, backgrounds were about 10. They were not affected by sample composition: at 8 amu the S mode background for real samples amounted to about 20, whereas at 220 amu it amounted to four counts. S and normal mode percentage 156 CeO + / 140 Ce ++ and percentage Ce ++ /Ce + ratios were about 1.5%, and temporal variations were insignificant. The percentage RSDs of normal and S mode Sr + , Ag + and Pb + isotope ratios were about 0.1%, with the exception of S mode 208 Pb + and 208 Pb + / 206 Pb + ratios in the presence of NaCl, which were degraded by a factor of about 2. Normal and S mode long-term variations for continuous aspiration of 0.1% NaCl for periods of up to 13 h were mass dependent, varying from 2.5-4% for 7 Li + and 9 Be + to about 2% for the mid-mass range, increasing slightly to about 3% for high masses. Most of this variation occurred during the first 100-150 min of the analysis during cone priming. With compensation, normal and S mode long-term percentage RSDs and drift were reduced to 1-2%. These variations indicate that extended periods of S mode analysis can be conducted without periodic recalibration. A calibration procedure, based on spiked HNO 3 , was validated by analysing spiked NaCl solutions, standard water and geological standard reference material (SRM) solutions with internal standardization using conventional solution delivery and flow injection. The agreement of the S mode data and the certified and literature values for ultratrace elements, including ppt levels of rare earth elements in the water standards, was satisfactory. An important conclusion is that ion sampling effects in the S mode are minimal and that the enhanced ion transmission interface is not only beneficial for microanalysis using laser ablation, but for geological and environmental