Understanding the process of microwave-assisted digestion combining diluted nitric acid and oxygen as auxiliary reagent

Bizzi, Cezar A.; Flores, Érico M.M.; Barin, Juliano S.; Garcia, Edivaldo E.; Nóbrega, Joaquim A.

doi:10.1016/j.microc.2011.05.002

Cited by 72 publications

(24 citation statements)

References 11 publications

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“…The use of diluted acids has several advantages, such as cost reduction, minimization of residues, reduction of blank values, and prevention of damages to equipment. 28,30,[39][40][41] All digestion procedures were evaluated by comparing the residual carbon content, the residual acidity of digests and the trace element recoveries. The residual carbon contents ranged from 4.0 ± 0.32 % to 14.9 ± 0.90% (n = 3).…”

Section: Optimization Of the Sample Digestion Proceduresmentioning

confidence: 99%

“…27 The experimental data suggested that the regeneration of HNO 3 could be explained by the oxygen atmosphere that improved the effectiveness of digestion using diluted nitric acid solutions. 28,30 The main purpose of this study was to develop a microwave-assisted digestion procedure, using diluted acid for the determination of trace elements in polychaete (Chaetopterus variopedatus). There is little information on the content of trace elements in the C. variopedatus polychaete.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microwave-assisted acid Digestion Procedure for Trace Elements Determination in PolychaeteChaetopterus variopedatus

Eça¹,

Brito²,

Barbosa³

et al. 2014

Revista Virtual De Química

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Procedimento de Digestão Assistido por Micro-ondas para Determinação de Elementos-traços no Poliqueta Chaetopterus variopedatusResumo: Este estudo avaliou e aplicou uma digestão, com ácido diluído, assistida por micro-ondas para determinar elementos-traço (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni e Sb) em amostras de poliquetas (Chaetopterus variopedatus). Após a otimização do método, empregando-se material certificado de referência (1566b CRM, tecido Oyster), os analitos foram determinados por espectrometria de massas com plasma indutivamente acoplado (ICP-MS) e espectrometria de emissão atômica com plasma indutivamente acoplado (ICP OES). A repetibilidade foi adequada (<10%), os resultados obtidos com o CRM concordaram com os valores certificados e o teor de carbono residual valores (RCC) foi menor do que 15%. Além disso, até dez amostras podem ser simultaneamente decompostas em 34 min., resultando num elevado rendimento. O método desenvolvido foi aplicado em amostras de poliquetas coletados na Baía de Todos os Santos, Bahia, Brasil. Palavras-chave:Elementos-traço; digestão assistida por micro-ondas; ácidos diluidos; tecido de poliquetas. AbstractThis study evaluated and applied a microwave-assisted diluted acid digestion to determine trace elements (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Ni and Sb) in polychaete (Chaetopterus variopedatus) samples. After the optimization of the method with certified reference material (CRM 1566b, Oyster tissue), the analytes were determined by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP OES). Repeatability was adequate (< 10 %), results for CRM agreed with the certified values and the residual carbon content (RCC) values were lower than 15 %. Moreover, up to ten samples can be simultaneously decomposed in 34 min., resulting in a high sample throughput. The developed method was applied to polychaete samples collected from Todos os Santos Bay, Bahia, Brazil.

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Section: Optimization Of the Sample Digestion Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microwave-assisted acid Digestion Procedure for Trace Elements Determination in PolychaeteChaetopterus variopedatus

Eça¹,

Brito²,

Barbosa³

et al. 2014

Revista Virtual De Química

View full text Add to dashboard Cite

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“…[28][29][30][31] However, it generally includes the use of concentrated acids and relatively high digestion time to achieve efficient matrix decomposition. 30 In this sense, the combination of ultraviolet radiation with microwave-assisted wet digestion (MW-UV) can be a suitable alternative to the digestion of seaweed samples.…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet radiation combined with microwave-assisted wet digestion of Antarctic seaweeds for further determination of toxic elements by ICP-MS

Mesko

Picoloto

Ferreira

et al. 2015

J. Anal. At. Spectrom.

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In this work, the use of ultraviolet radiation combined with microwave-assisted wet digestion (MW-UV) was applied for digestion of seaweed samples and further determination of As, Cd and Pb by inductively coupled plasma mass spectrometry (ICP-MS). In the proposed method, UV radiation was generated in situ by electrodeless Cd discharge lamps inserted into digestion quartz vessels. This approach increased the digestion efficiency allowing lower consumption of acids. The feasibility of using diluted acid solution (0.5 to 7 mol L À1 HNO 3 ) was evaluated for relatively higher sample masses (up to 800 mg). The efficiency of digestion was evaluated taking into account the residual carbon content and residual acidity in digests. Under the selected conditions, it was possible to digest up to 700 mg of sample using a nitric acid solution as diluted as 2 mol L À1 HNO 3 allowing an efficiency of digestion higher than 77% (considering the total C content in the sample) and acidity as low as 0.19 mol L À1 that is convenient for ICP-MS measurements. The accuracy of the proposed MW-UV method was evaluated by the digestion of two certified reference materials of aquatic plant (BCR 060 and BCR 670) and by comparison with the results obtained after digestion by microwave-assisted wet digestion in a high pressure system using concentrated HNO 3 (MW-AD). The results obtained by the proposed method did not present difference (t-test, 95% confidence level) with the certified values and with results obtained after seaweed sample digestion using the MW-AD method. Using 700 mg of sample, the limit of detection was 0.005, 0.001, and 0.012 mg g À1 for As, Cd, and Pb, respectively. A clear advantage of the proposed method over classical approaches is that only diluted solution was necessary and it is possible to digest a relatively high sample mass, that is important to minimize the generation of laboratory residues and to improve the limits of detection, respectively.

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“…Most definitions are based on different physico-chemical properties, specifically in their different densities and their relative atomic mass (between [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. As a result, the number of elements that are considered as "heavy metal" varies widely from one author to another (1)(2)(3)(4).…”

Section: Introductionmentioning

confidence: 99%

Determination of heavy metals in marine sediments using MAME-GFAAS

Hernández-Martínez

Padrón-Sanz

Torres-Padrón

et al. 2015

J. Anal. At. Spectrom.

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A new green method has been developed for the extraction of the pseudo-total content of the heavy metals Ni, Cu, Cr, Pb, and Cd from marine sediments using a mixture of biodegradable micellar media (SDS, Triton X-100) as extractants and graphite furnace atomic absorption spectrometry (GFAAS) for their determination. This work is the first one that uses only surfactants as extractants, without the addition of chelating agents to increase the extraction efficiency of the method, proving to be effective in the extraction of metals from this type of matrices. The proposed method has shown high recovery percentages for all the metals considered (>68%), good linearity and reproducibility (RSD<5.9%), as well as detection limits ranging from 0.06 to 2.78 µg g -1 . The method was applied to the determination of the heavy metals under study in samples with different physicochemical properties. Finally, our results were compared with those obtained using microwave assisted extraction -furnace atomic absorption spectrometry (MAE/GFAAS) described in ISO 11047:1998 obtaining comparable results.Nevertheless, Hübner et al. (5) raise four different options for the use of the term "heavy metal", although they suggest that the term applies to the following elements: arsenic, cadmium, chromium, cobalt, copper, lead, mercury, nickel, tin and zinc. Heavy metals considered in this study (Ni, Cr, Cu, Pb and Cd) are categorized as priority pollutants by the U.S. Environmental Protection Agency (6). They have proved to be important pollutants in the marine environment, with high toxicity, long persistence and rapid accumulation at living organisms (7-9).Due to the hydrophobic behaviour of these metals, their concentration in seawater is very low, and they instead tend to accumulate in marine sediments (8)(9)(10)(11)(12). This trend is due to adsorption, co-precipitation and metal complexation in the surface layers of fine sediment particles. Thus, four types of metal fractions can be distinguished: (a) the exchangeable fraction, which is located in the ion exchange sites and it is freely available to take part in chemical reactions, (b) the reducible fraction, consisting of complex oxides and hydroxides, which is soluble under reducing conditions, (c) the oxidizable fraction, which is formed with the organic matter and sulphides, and

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Understanding the process of microwave-assisted digestion combining diluted nitric acid and oxygen as auxiliary reagent

Cited by 72 publications

References 11 publications

Microwave-assisted acid Digestion Procedure for Trace Elements Determination in PolychaeteChaetopterus variopedatus

Microwave-assisted acid Digestion Procedure for Trace Elements Determination in PolychaeteChaetopterus variopedatus

Ultraviolet radiation combined with microwave-assisted wet digestion of Antarctic seaweeds for further determination of toxic elements by ICP-MS

Determination of heavy metals in marine sediments using MAME-GFAAS

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