Preparation steps in environmental trace element analysis — facts and traps

Hoenig, M.

doi:10.1016/s0039-9140(01)00329-0

Cited by 157 publications

(75 citation statements)

References 22 publications

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“…Thus, in more complex matrices, compounds such as proteins, fat or silicates suffer incomplete digestion and remain as interferents on the final residue. 22 In microwave digestion, heating results from the sample's molecular interaction with electromagnetic waves: 42,43 generated heat is dissipated from within the irradiated medium; as radiation flows through the reactor walls without being absorbed, no energy is lost, resulting in significantly faster heating with the possibility of attaining higher digestion temperatures. The choice of nitric acid as the digestion reagent is due to the fact that being a powerful oxidizer it can decompose or mineralize a large range of samples with a complex nature.…”

Section: Resultsmentioning

confidence: 99%

“…15,16 However, SWASV is susceptible to errors arising from the presence of organic matter 17,18 and therefore, when complex matrixes, 19-21 either industrial, biological and/or environmental, are under investigation, sample pre treatment is of vital importance because it allows one to minimize the errors caused by organic interferents. 22 This aspect leads to the need of a method allowing an efficient removal of contaminants prior to analysis. The most convenient procedure involves sample decomposition, which basically consists on the oxidation i.e, mineralization of organic material into carbon dioxide, nitrogen oxides and water 22 usually by the use of a strong acid.…”

Section: Introductionmentioning

confidence: 99%

“…22 This aspect leads to the need of a method allowing an efficient removal of contaminants prior to analysis. The most convenient procedure involves sample decomposition, which basically consists on the oxidation i.e, mineralization of organic material into carbon dioxide, nitrogen oxides and water 22 usually by the use of a strong acid. In this process, commonly designated as sample acid digestion, reagents, temperature and digestion time are significant variables that must be optimized for each particular sample since they depend on both the nature and composition of the sample matrix.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous monitoring of toxic metals on white poplar (populus) by SWASV

Silva¹,

Lopes²,

Leitão³

et al. 2005

J. Braz. Chem. Soc.

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foi utilizada na determinação simultânea de quantidades traço dos metais tóxicos Pb(II), Cd(II) e Cu(II) em folhas de choupo (populus), utilizadas como bio-indicador, recolhidas numa área de tráfego automóvel intenso da cidade de Lisboa. As folhas, após secagem, foram submetidas a um processo de digestão ácida por microondas. Para a aplicação desta técnica à análise das folhas foi realizado um estudo de optimização dos vários parâmetros voltamétricos. O eletrodo de trabalho consistiu num filme de mercúrio depositado numa superfície de carbono vítreo. O sistema Ag/AgCl foi utilizado como referência e um fio de Platina como eletrodo auxiliar. Concentrações médias (em mg de metal/kg de matéria seca -folhas) de 2,6, 0,18 e 5,0 foram obtidas para o Pb(II), o Cd(II) e o Cu(II), respectivamente. O valor obtido para o chumbo coincide com o obtido pelo método de referência baseado na Espectrofotometria de Absorção Atômica em Forno de Grafite (EAAFG).Square wave anodic stripping voltammetry (SWASV) was applied to the simultaneous determination of trace amounts of toxic metals Pb(II), Cd(II) and Cu(II) in white poplar (populus) leaves, used as bio indicator and gathered in a chosen area of the city of Lisbon with very high traffic intensity. The leaves were dried and subsequently exposed to an acid digestion microwave process. Square wave parameters were optimized for the voltammetric analysis of the samples. The working electrode consisted of a thin mercury film (TMFE) deposited on the surface of vitreous carbon. The pair Ag/AgCl was used as the reference electrode and a Pt wire as the auxiliary electrode. Average concentrations (in mg of metal/kg of dry matter-leaves) of 2.6, 0.18, and 5.0 were obtained for Pb(II), Cd(II) and Cu(II), respectively. The value for lead coincides with the one obtained by the reference method based on Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Simultaneous monitoring of toxic metals on white poplar (populus) by SWASV

Silva¹,

Lopes²,

Leitão³

et al. 2005

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

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“…Wet mineralization can be carried out in both open and closed systems; the latter is particularly indicated in trace analysis, as it helps to avoid analyte loss and secondary contamination of the sample. In addition, the decomposition can be carried out at elevated temperature and pressure, as a result of which the process takes less time Hoenig, 2001).…”

Section: Extraction Techniquesmentioning

confidence: 99%

The speciation and physico-chemical forms of metals in surface waters and sediments

Namieśnik

Rabajczyk

2010

Chemical Speciation & Bioavailability

143

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Surface waters can be contaminated in many ways, e.g., by solutions and suspended matter. Moreover, insoluble substances in colloidal form, in suspension or adsorbed on solid bodies can dissolve in response to changing physical and chemical conditions and become a secondary source of surface water pollution, thereby endangering wildlife. In addition, if we take into account varying rates of flow, contaminants can be transported over considerable distances. Hydrological processes, which determine factors, such as the rate of sedimentation, also influence the quality of surface waters; bottom sediments can contain large quantities of accumulated organic and inorganic compounds, including heavy metals. The physical and chemical properties of aquatic ecosystems are characterized by a number of interdependent parameters. Hence, factors such as temperature, oxygen content and pH of a water body can alter the solubility of the salts present in it, the forms of occurrence of particular species, as well as their bioavailability and toxicity. Thus it is necessary to determine the various species of metals present in the different compartments of the aquatic ecosystem.

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“…Most of the methods of decomposition used in elemental analyses are based on digestion with strong acids (HNO 3 , HCl, H 2 SO 4 , HF) at elevated temperatures, which can lead to the loss of easily volatile elements such as As, Sb, Se and Sn [25][26][27]. The microwave accelerated digestion has become the most commonly used method for the determination of toxic element concentrations in solid samples by ICP-OES [25,28,29].…”

Section: Introductionmentioning

confidence: 99%

An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

Ilander¹,

Väisänen²

2007

Analytica Chimica Acta

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A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg II 280.270 nm / Mg I 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min -1 , auxiliary gas flow of 0.2 L min -1 and plasma power of 1400 W were used for radially viewed plasma.The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydro fluoric acid (HF) resulted in recovery rates of over 81 %. One exception is arsenic which resulted in recoveries of about 60 % only; however, it could be digested with good recovery (> 90 %) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min).

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Preparation steps in environmental trace element analysis — facts and traps

Cited by 157 publications

References 22 publications

Simultaneous monitoring of toxic metals on white poplar (populus) by SWASV

Simultaneous monitoring of toxic metals on white poplar (populus) by SWASV

The speciation and physico-chemical forms of metals in surface waters and sediments

An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

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