A rapid ultrasound-assisted thiourea extraction method for the determination of inorganic and methyl mercury in biological and environmental samples by CVAAS

This study outlines the development of a procedure for the determination of methylmercury by anodic stripping voltammetry at a gold nanoparticle-modified glassy carbon electrode (AuNPs-GCE) and for the differentiation between methylmercury and inorganic mercury. The signal of methylmercury was measured in the square wave mode using HCl as the supporting electrolyte. The procedure had good accuracy, repeatability and linearity. The determination of total mercury in solutions containing both methylmercury and inorganic mercury was performed after converting the former into the inorganic form. Different sample solution pre-treatments were tested for this purpose, and an acid digestion in a microwave oven with HNO 3 and H 2 O 2 was found to be the most effective. The selective determination of methylmercury in the presence of inorganic mercury was possible after masking the latter through reduction to the elemental state with SnCl 2 . The amount of inorganic mercury was determined by difference.

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“…elemental mercury with SnCl 2 and the total mercury content is measured after sample mineralization [51,54].…”

Section: Determination Of Total Mercurymentioning

confidence: 99%

Voltammetric determination of methylmercury and inorganic mercury with an home made gold nanoparticle electrode

et al. 2009

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“…Inorganic mercury has been reported to produce harmful effects at concentrations as low as 5 g/L [1]. Inorganic mercury may be converted to methylmercury in marine environment that is even more toxic than the inorganic mercury [2]. Methylmercury triggers several serious disorders for humans including allergic reactions and brain and neurological damage.…”

Section: Introductionmentioning

confidence: 99%

A new Schiff's base ligand immobilized agarose membrane optical sensor for selective monitoring of mercury ion

Alizadeh

Parooi

Hashemi

et al. 2011

Journal of Hazardous Materials

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“…Thus, CVG has also been interfaced to ICP-MS as an attractive sample introduction method to enhance the sensitivity in determination of this ubiquitous and toxic element [42-45]. Acidic stannous chloride (SnCl 2 ) solution is frequently used as reductant provided that all Hg species in the sample are converted to Hg(II) by means of vigorous acid digestion or reacting with strong oxidizing agents (e.g., KMnO 4 ) [38, 41-43). In this study, we opted for NaBH 4 as it can reduce both inorganic and organic forms of Hg [36, 39, 44].…”

Section: Resultsmentioning

confidence: 99%

Determination of mercury in fish otoliths by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS)

Kendüzler

Ateş

Arslan

et al. 2012

Talanta

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A method based on cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS) has been developed for determination of inorganic mercury, Hg(II), and total mercury in fish otoliths. Sodium borohydride (NaBH4) was used as the only reducing agent and its concentration was optimized across an acidity gradient to selectively reduce Hg(II) without affecting methylmercury, CH3Hg(I). Inorganic Hg was quantitatively reduced to elemental mercury (Hg0) with 1×10−4% (m/v) NaBH4. CH3Hg(I) required a minimum of 0.5% (m/v) NaBH4 for complete reduction. Increasing the HCl concentration of solution to 5% (v/v) improved the selectivity toward Hg(II) as it decreased the signals from CH3Hg(I) to baseline levels. Potassium ferricyanide solution was the most effective in eliminating the memory effects of Hg compared with a number of chelating and oxidizing agents, including EDTA, gold chloride, thiourea, cerium ammonium nitrate and 2-mercaptoethylamine chloride. The relative standard deviation (RSD) was less than 5% for 1.0 μg L−1 Hg(II) solution. The detection limits were 4.2 and 6.4 ng L−1 (ppt) for Hg(II) and total Hg, respectively. Sample dissolution conditions and recoveries were examined with ultra-pure CaCO3 (99.99%) spiked with Hg(II) and CH3HgCl. Methylmercury was stable when dissolution was performed with up to 20% (v/v) HCl at 100 oC. Recoveries from spiked solutions were higher than 95% for both Hg(II) and CH3Hg(I). The method was applied to the determination of Hg(II) and total Hg concentrations in the otoliths of red emperor (CRM 22) and Pacific halibut. Total Hg concentration in the otoliths was 0.038 ± 0.004 μg g−1 for the red emperor and 0.021 ± 0.003 μg g−1 for the Pacific halibut. Inorganic Hg accounted for about 25% of total Hg indicating that Hg in the otoliths was predominantly organic mercury (e.g., methylmercury). However, as opposed to the bioaccumulation in tissues, methylmercury levels in otoliths was very low suggesting a different route of uptake, most likely through the deposition of methylmercury available in the water.

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A rapid ultrasound-assisted thiourea extraction method for the determination of inorganic and methyl mercury in biological and environmental samples by CVAAS

Cited by 77 publications

References 49 publications

Voltammetric determination of methylmercury and inorganic mercury with an home made gold nanoparticle electrode

Voltammetric determination of methylmercury and inorganic mercury with an home made gold nanoparticle electrode

A new Schiff's base ligand immobilized agarose membrane optical sensor for selective monitoring of mercury ion

Determination of mercury in fish otoliths by cold vapor generation inductively coupled plasma mass spectrometry (CVG-ICP-MS)

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