Comparative study of magnesium nitrate, palladium nitrate and reduced palladium for the direct determination of mercury in sea water by electrothermal atomization atomic absorption spectrometry

Bermejo–Barrera, Pilar; Moreda–Piñeiro, Jorge; Moreda–Piñeiro, Antonio; Bermejo-Barrera, Adela

doi:10.1007/bf01244963

Cited by 13 publications

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References 18 publications

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“…In most attempts, Pd proved to be the most effective chemical stabilization alone [18–20] or as a mixed-modifier with magnesium nitrate [18, 19], potassium permanganate [21] and DDC [22], though silver nitrate (AgNO 3 ) and potassium permanganate (KMnO 4 ) also afforded accurate determinations in fast-furnace programs without Pd [23]. Calcium nitrate was reported to be suitable for stabilization of As [15, 16, 20] and boron (B) [25] during atomization from graphite platforms.…”

Section: Resultsmentioning

confidence: 99%

Assessment of matrix-dependent analyte stability and volatility during open-vessel sample dissolution for arsenic, cadmium, mercury and selenium

2009

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The effects of calcium and magnesium (as nitrates) and phosphorous (as hydrogen phosphate) were investigated on the stability of As, Cd, Hg, and Se during open-vessel dissolution in Teflon vessels. Samples of mainly inorganic and biological matrices were dissolved in screwcapped Teflon tubes in HNO 3 only or in a mixture of HNO 3 -HF. The caps were then removed and the solutions were simultaneously evaporated at 120 °C to near dryness without drying the contents (Method I) or to complete dryness with extended heating for 20 min at dryness (Method II). ICP-MS analysis indicated that the stabilities of Se and Hg were highly influenced by Ca, Mg and PO 4 content in the sample. Arsenic (As) and Cd did not show any significant instability or volatility. Selenium was lost in Method II from biological samples containing trace levels of Ca, Mg and PO 4 . Mercury was unstable during heating in all samples, except bone ash for which no significant loss was detected in Method I. Losses observed for Hg and Se were consistent with Ca, Mg and PO 4 deficiency in the samples and hence indicated that nitrate and hydrogen phosphate salts of these matrix elements do improve stability of the relatively volatile elements during openvessel dissolution in teflon vessels. While Se was effectively stabilized with sub-per cent levels of Ca, Mg and PO 4 , Hg due its high volatility required significantly higher levels of Ca and PO 4 in the bone ash.

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Section: Resultsmentioning

confidence: 99%

Assessment of matrix-dependent analyte stability and volatility during open-vessel sample dissolution for arsenic, cadmium, mercury and selenium

2009

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Heavy Metals Analysis in Seawater and Brines

Troccoli

2000

Encyclopedia of Analytical Chemistry

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There has been growing concern during and since the 1990s about the effect that the toxicity and persistence of heavy metals will have on the biosphere. Consequently, these new environmental pressures have challenged analysts to find better experimental procedures for handling, recognition and evaluation of traces of heavy metals. Moreover, the determination of low levels of heavy metals in seawater has received particular attention as a way of assessing the early impact of human activities on the marine environment. It is necessary to protect the marine and continental waters against contamination so as to allow suitable conditions for the maintenance of aquatic life and the various uses derived from aquatic life. It is not the metal concentration alone that enables an environmental diagnosis to be made but the way metal combines with other elements to form species. These species are responsible for the biological behavior of the heavy metal under consideration, as its bioavailability will determine the amount of harm it may cause. Thus, “speciation” studies should be conducted to assess the potential environmental impact of human activities. From the analytical point of view, seawater and brines may be considered to be closely related systems in terms of matrix effects and analytical difficulties. Hence these two systems will be included in this article although the aims of heavy metal detection and determination might be diverse in each case. Analytical inaccuracies that arise from the high salt content of the seawater or brine solutions are exacerbated by the low levels of trace metals, which require careful control of contamination during sample collection and analysis and very sensitive analytical techniques. Different techniques for the determination of trace metals in seawater, such as spectroscopic and electroanalytical methods, will be discussed here in terms of their performance in dealing with the problem of trace metal detection and determination. Even the term “trace” has had different meanings over the years, normally being associated with the detection limit of the technique employed (“traces”, “footprints” or “trails” have a lot to do with the way they are observed). Amounts that would have been considered traces in the 1960s are probably no longer considered as such in the 1990s, as detection limits for most heavy metals have been lowered by three to six orders of magnitude (using “state of the art” techniques) since the late 1960s. Special attention has been paid to the preconcentration of the analyte and its isolation from the matrix constituents which might obscure its accurate determination. A variety of separation–preconcentration methods will be presented, with a strong bias towards those procedures leading to some kind of automation, because pretreatment of the samples is often time‐consuming and prone to contamination and may lead to an incomplete recovery of the analytes. Flow injection analysis (FIA) has appeared as a solution to time‐consuming and complicated separations and it will also be discussed in relation to alternative forms of analysis, especially in terms of its ability to perform speciation studies.

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1998

Atomic Absorption Spectrometry

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Comparative study of magnesium nitrate, palladium nitrate and reduced palladium for the direct determination of mercury in sea water by electrothermal atomization atomic absorption spectrometry

Cited by 13 publications

References 18 publications

Assessment of matrix-dependent analyte stability and volatility during open-vessel sample dissolution for arsenic, cadmium, mercury and selenium

Assessment of matrix-dependent analyte stability and volatility during open-vessel sample dissolution for arsenic, cadmium, mercury and selenium

Heavy Metals Analysis in Seawater and Brines

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